GEOM2001 FINAL REVISION SET!

Which of these database calculations returns a Boolean (true/false) result. "OBJECTID" > 1000 "AREA" / 10000 ABS ("AREA") "OBJECTID" + 1000

"OBJECTID" > 1000

Which of these is NOT considered a spatial query (e.g. select by location): "Waterbody" within 50 meters from "Roads" "Waterbody" Area > 100 hectares "Road" features within selection box "Waterbody" overlaps ("Region" = "Richlands")

"Waterbody" Area > 100 hectares

metadata

'data about data' good practice to create metadata for all data can view using ArcCatalog (select data in catalog tree, click on description tab) many standards created to coordinate metadata practices like international organization for standardization's (ISO) important q's: are the data current for the time period? TIME PERIOD OF CONTENT. is the listing exhaustive? completeness. what is the operating definition of 'park' that was used by the creators of this table? universe. how authoritatie is the source for these data? citation. PURPOSE? PROCESSING STEPS? transformation? what format are the data in? regarding spatial data: referencing system and spatial precision information

critiquing maps

'deconstructing the map' 'critical' representation of the world

neogeography

'new geography' and consists of a set of techniques and tools that fall outside the realm of traditional GIS about people using and creating their own maps, on their own terms, and by combining elements of an existing toolset. sharing location information with friends and visitors, helping shape context, and conveying understanding through knowledge of place term by Di-Ann Eisnor 2006 contrast between perceived tedious, slow boring and expensive practices of cartographers and georaphers, versus enjoyable rule breaking and relevant uses of GI by laypersons

Given spatially integrated layers A and B (i.e. the OUTPUT from overlay UNION), what features would be part of the an overlay INTERSECT.

(A = 1 OR A = 2) AND B = "X"

Describe what the Geoweb is and three advantages of the GeoWeb.

(also known as distributed GIS) the different parts of the GIS can be in very different locations but linked through the internet 1. Reduced server costs to individuals 2. Users and subject areas can be in the same place 3. GIS processing can be distributed across the internet (cloud platform GIS and service-oriented architecture)

Types of GIS architecture

-Desktop -Client server (one DBMS to several PCs) -desktop sharing files (desktop GIS on PCs sharing files on a PC server via LAN) -Centralised servers -Geoweb (distributed)

Dijkstra's Algorithm

1. 'tentative' distance 2. start at initial node 3. calculate distance to neighbors 4. move to node with smallest 'tentative' distance 5. go to step 3 6. continue until destination has been visited

Examples of when to use Continuous Fields

1. Interval or ratio data 2.Where values vary continuously over geographic space

Examples of when to use Discrete objects

1. Nominal or ordinal data 2. Discrete entities 3. To delineate boundaries

In developing GIS data models of the real-world there are four components that are required. Order the components below in terms of increasing abstraction (i.e., order from 1 = least abstracted to 4 = most abstracted).

1. Reality 2. Conceptual Model 3. Logical mode 4. Physical Model

steps for database creation

1. data investigation: consider type, quantity, qualities of data to be included in the database, the nature of the entities and attributes is decided (inventory of data, needs analysis) 2. relationship modeling: form a conceptual model of data by examining the relationships between entities and the characteristics of entities and attributes (ERM or EAM) 3. Database design: creation of a practical design for the database. This step depends upon and is constrained by the software being used. Field names, specific attribute types and structures (like tables) are decided 4. Database implementation: populating the database with attribute data. this is followed by monitoring and upkeep, fine tuning, modification and updating

steps in MCE

1. define a problem. range of criteria that will influence the decision must be defined, criteria as data layers. selection of criteria 2. standardization of criterion scores. standardization of the scales of measurement used by data layers. 3. allocation of weights. 0-1 4. applying the MCE algorithm. sum them

Multi Criteria Evaluation

1. input layers 2. standardize 3. weight 4. combine either supplement or replace standard map overlay in GIS MCE techniques allow map layers to be weighted to reflect their relative importance and unlike polygon overlay in vector GIS, they don't rely on threshold values so MCE provides a framework for exploring solutions to decision-making problems, which may be poorly defined combining data according to their important in making a given decision involves qual and quant weighting, scoring or ranking of criteria to reflect their importance to either a single, or a multiple set of objectives. numerical algorithms that define the 'suitability' of a particular solution on the basis of hte input criteria nad weights together with some math or logistical means of determining trade offs when conflicts arise

Main sources of error during data capture?

1. positional accuracy 2. Attribute Accuracy 3. Logical Consistency 4. Completeness

raster: polygon-on-polygon

1. using add function for UNION (OR) overlay. 2. multiply layers for INTERSECTION (AND) overlay

Sources and types of data capture errors

1.Positional Accuracy - is the expected difference in the measured geographic location of an entity from its true ground position Absolute accuracy refers to accuracy with respect to a coordinate system. Relative accuracy refers to accuracy with respect to the positioning of geographic entities relative to each other. 2.Attribute Accuracy -is the accuracy of the non-spatial attributes of geographic features (i.e., what they are) 3.Logical Consistency - concerned with determining the faithfulness of the data structure for a data set. This typically involves spatial data inconsistencies ,such as incorrect line intersections, duplicate lines or boundaries, or gaps in lines. These are referred to as spatial errors 4. Completeness refers to how complete a data set is. This includes consideration of holes in the data, unclassified areas, and any compilation procedures that may have caused data to be eliminated

John Krygier and Jeremy Crampton's argument

2 assertions about these 2 ^ critical movements of cartography: 1. critique is political by its nature 2. today's critical movement is part of a longer cartographic critique. mapping throughout history has been continually contested. explicit critique of cartography and GIS that rose in late 1980s should be understood in this much longer tradition.

Buffers

2 fundamental approaches: buffer the source feature and determine where the target features are within that buffer (buffer industrial emitters and determine which schools fall within that radius) determine the shortest distance from each target feature to the source features-a spatial join in ArcMap (measure the distance from each school to the nearest industrial emitter) which to choose depends on what follows and how you wish to visualize the results can only be done using vector data buffering used to find a zone of interest around an entity or set of entities. around point features is easiest, lines and areas are more complex.

Given spatially integrated layers A and B (i.e. the OUTPUT from overlay union); if you queried polygons where A=1 how many would be selected.

3

critical GIs/cartography

3 major components: 1 links geographic knowledge with political and social power 2. uncovers the political motivations and assumptions of mapping 3 opens up the use of mapping and GIS to everyone- certain motivations and processes of neogeography are therefore linked to critical GIS and cartography, making consumers of geographic knowledge into producers. knowledge is a form of power

Given the two input rasters below; what is the result in the top row of cells for the raster operation: [INPUT A] + [INPUT B]

3,3, null

Given the tables for FACES; what ID's are retrieved for the query (note <> means not equal): select ID from FACES where State<>'happy' AND Shade='dark'

3,5

You can superimpose a two-dimensional features or images data layer on top of a surface layer and obtain its z-value to make a more realistic view of the landscape. What is this process called in GIS?

3D draping

What is the minimum number of satelittes required to determine your location accurately using a GPS? 4 1 3 2

4

If you convert a raster from a resolution of 1 meter to a resolution of 10 meters, what is the trade-off between spatial accuracy (i.e. pixelation) and size (i.e. number of cells) of raster: A 10 meter raster is more accurate but larger size A 10 meter raster is more accurate but smaller size A 10 meter raster is less accurate but larger size A 10 meter raster is less accurate but smaller size.

A 10 meter raster is less accurate but smaller size.

Queries: Boolean operators

A AND B=intersect A OR B = UNION A NOT B= CLIP A XOR B =SYMMETRICAL DIFFERENCE

Suppose you needed to choose a projection to calculate the direction between two villages. Which one of the following projections would be the best one to use? A Plate Caree projection A conformal projection An equal area projection A cylindrical equal area projection

A conformal projection

Suppose you needed to choose a projection to calculate the direction between two villages. Which one of the following projections would be the best one to use? A cylindrical equal area projection A Plate Caree projection A conformal projection An equal area projection

A conformal projection

Suppose you needed to choose a projection to calculate the direction between two villages. Which one of the following projections would be the best one to use? A Plate Caree projection A cylindrical equal area projection An equal area projection A conformal projection

A conformal projection

GIS definition

A digital system for acquisition, management & visualisation of spatial info. A complex of software, hardware, data, people/institutions, activities/procedures and networks. It is a decision support system.

Run length encoding

A form of raster data compaction in the format of [number, no. repeats]

A contour line is: A line that follows the ridge of a hill A line that connects points of equal surface value A line that defines the boundary of NoData areas on a raster A line that profiles steepness on a 3D surface

A line that connects points of equal surface value

Attribute Queries

A request for records of features in a table based on their attribute valuesAttribute join -creates a table view (for display and queries) as the combination of two tables based upon matching values between fields

Data model definition

A set f constructs for representing objects & processes in a digital environment Allows geographic features to be represented & stored digitally so they can be abstractly represented in map form.

Data Model

A set of constructs for representing objects and processes in the digital environment of a computer

To display a raster image (such as an air photo) in 3D perspective, you can set its base heights to which of the following layers?

A spatially coincident TIN or elevation raster

Indicate which of these data queries has a Valid or Invalid logical syntax. "Income" > 1000 AND < 500000 "Last_Name" = "Adams" "Last_Name" = "Adams" OR "Last_Name" < 2000 "Last_Name" = "Adams" OR "Income" < 2000 A = Valid B = Invalid

A, B, A, B

intersect

AND retain common features

Which of these is NOT a service provided in relational database management systems:

Ability to reclass data attribute using methods such as natural breaks, quantile and standard deviation classification.

Which of these is NOT a service provided in relational database management systems: Controlled access for data security Multi-user access to database Ability to reclass data attribute using methods such as natural breaks, quantile and standard deviation classification. Supporting referential integrity on feature (or record) identifiers so they are unique.

Ability to reclass data attribute using methods such as natural breaks, quantile and standard deviation classification.

Which of these is NOT a service provided in relational database management systems

Ability to reclass data attribute using methods such as natural breaks, quantile and standard deviation classification. Supporting referential integrity on feature (or record) identifiers so they are unique.

Which one of the following best describes the difference between positional accuracy and precision? Accuracy describes the extent to which the position reflects the true real-world position, while precision is the exactness of the position Accuracy refers mainly to non-spatial attributes, while precision refers mainly to spatial atttributes Accuracy is the exactness of the position, while precision describes the extent to which the position reflects the true real-world position They refer to roughy the same thing

Accuracy describes the extent to which the position reflects the true real-world position, while precision is the exactness of the position

LiDAR and its Uses

Active form of remote sensing measuring distance to target surfaces by illuminating the target with a laser and analysing the reflected light pulses Create Terrain and Surface Models LiDAR data is ideal for terrain analysis as it has a spatial resolution of 0.5 to 2 metres and a vertical accuracy of about 15 centimetres

Different Ways to Combine Suitability

Additive weighted combination: individual criteria compensate for others Geometrical weighted combination: individual criteria limit influence of others Ideal point method: Closeness to an ideal and distance from the worst

3 elements to topology

Adjacency (share same boundary) Connectivity (bound at a point bound at in real life) Containment (one contained in another)

Elements of Topology

Adjacency, connectivity, and containment (enclosure)

Advantages of and challenges of the GeoWeb (privacy, data ownership, training)

Advantages 1. Allows users to integrate disparate sources of data (mashups) 2.GIS processing can be distributed across the internet (cloud platform GIS and service-oriented architecture) 3.Reduced server costs to individuals 4.Users and subject areas can be in the same place (location based services & mobile GIS) Challenges GIS training Data standards and specifications Ethical issues, privacy and data ownership. Who owns the data and does copyright protect the economic value of data?

Types of transformation in georeferencing

Affine (3 points) Second order polynomial (6) Third order polynomial (10)

Explain the apparent conflict between Mark Monmonier's assertion that 'all maps tell lies' and that 'maps must be accurate, truthful, complete, useable and useful'.

All maps tell lies due to 1. The world is an infinitely complex place. 2. Maps cannot represent all of this infinite complexity. Additionally the world is an ellipsoid and maps are normally flat, therefore projections are required that are not always a complete reflection of earth. The second statement despite conflicting is also important, as maps are needing to be as accurate, truthful and complete as possible so the uses, interpretations and decisions to be made on the basis of the maps are feed right information. An example is resolution, current resolution is what is practical it would be impractical if the earth was full manually surveyed and once this task would be completed it would be like the Sydney Harbour Bridge you would need to start painting again because half of it would be inaccurate. So maps some be as accurate as practically possible for the decision it is used for.

12 Basic Elements of Maps

All maps: Scale, Direction, Legend, Lineage Context: Title, Projection, Cartographer, Date of production Effective Communication: Neat line, Locator map, Inset map, Index map

Figure-ground organisation

Allow focus on figure rather than group

Which one of the following is NOT a benefit of cloud platform GIS? a. Allows a cheaper business model b. Allows scalability c. Allows the application of new data models d. Allows rapid deployment

Allows the application of new data models

New 3D data models can be integrated into this technology b. Allows easy re-projection of data Multi-media can easily be integrated with GIS data

Allows the user and subject area to be in the same place

Mollweide Projection

An equal-area map projection that is an ellipse.

Common ways of modelling geographic phenomena are as continuous surfaces (represented as a raster) and discrete objects (represented as a vector). Discuss, using examples, what are the advantages and limitations of each method.

An example of a continuous surfaces is soil, an example of a count

Describe three type of distortion that can occur when geographic data are projected onto a flat surface.

Area, distance, direction and shape distortions all occur when geographic data is projected. As an example one cannot remove an orange skin and lay it perfectly flat without tearing it. Often it depends on the purpose of the projection as to how it is distorted. For navigational purposes, areas, shapes and distances will be distorted at larger level but in a small area direction will be preserved. If the map is needed for area purposes it is often distorted in shape and direction to preserve area.

Briefly discuss what is meant by "Cartography is the art, science and technology of map making and use". Explain why graphical scale should always be included on a map in digital mapping.

Art because there is subjectivity and some ability to be creative i.e. colours and presentation, in order emphasis the main purposes and results of the map. In lester year, due to manual efforts, map would have been included more art. Science because it is accuracy, procedure and integrity to procedure a map. No skewing data or presenting unfounded opinion but rather presenting accuracy result founded on the basis of scientific integral procedures. Technology is important to facilitate map making and capture accurate data in particular within the GIS world to which we live in today. Important to understanding the limitations of the technology used in order to interpret the map.

Cartography

Art, science & technology of map making and use. Goal is to communicate spatial info effectively and efficiently.

Which of the following statements about Aspect is NOT true? Aspect is the compass direction in which a slope faces Aspect identifies the up slope direction from each cell to its neighbours Aspect is measured clockwise in degrees from 0 to 360 None of the above

Aspect identifies the up slope direction from each cell to its neighbours

Root mean square error is used in georeferencing to

Assess the goodness of fit to control points. Doesn't measure control point distortion. Ideally choose a transformation system that minimises root mean square error.

Defining and Interpreting weights

Assign weight to each criteria to signify the relative importance of one criteria or another Methods: Rank Importance, Directly Assign weights, voting methods, survey

Which one of the following is a mashup? a. ArcGIS b. Landsat satellite imagery c. A 3D map d. Atlas of Living Australia

Atlas of Living Australia

Which one of the following would be best represented by a continuous field? Roads Atmospheric pressure Buildings Vegetation communities

Atmospheric Pressure

Equal area

Attempts to preserve areas of features useful for calculating area

Equidistant

Attempts to preserve distances Useful for calculating distances

Relational DBMS Model

Attribute Table With Primary Key, attributes, and tuples most popular type of DBMS Commercial systems: IBM DB2, Informix, Microsoft SQL Server, Oracle

A confusion, or error, matrix is one way to assess which one of the following?

Attribute accuracy

Types of raster layers

Base (e.g. aerial photo) Thematic (e.g. land use) Surface (e.g. elevation) Attributes (e.g. geotagged photo)

Imagine you have been given the task of calculating the total area of vegetation cover across Queensland. Describe what type of data you might use to do this (e.g., in-situ or remotely sensed data) and what type of projection you would use and why.

Because the problem is largely to do with area, an equal area projection would be most appropriate. Satellite images could be used for ex-situ (remote sensed) data determining which areas have vegetation. in-situ dat

When georeferencing, which one of the following does the Affine (1st order polynomial) transformation NOT do? Bends Shifts Scales Rotates

Bends

How would you exclude areas within 50 meters of a river for a land suitability study using GIS analysis:

Buffer the river and overlay ERASE it with other land features

3D City Models and their applications

Build Flexible Scenarios Compare and analyze building proposals from every angle. See how they fit into your city's overall vision for the future. Make as many scenarios as you need and add modifications. This saves you time and money. Create Realistic Context See where a proposed building blocks the view, casts shadows, and reflects heat. By making the virtual 3D visualization as real as possible in the design phase, you will avoid costly mistakes in the building phase. Share Your Plan Online Publish your 3D model online. Others can interact with it, understand your urban plan, and participate in improving their community.

What is the typical way for relating column data in one table to another table:

By table join based on common fields in both tables.

What is the typical way for relating column data in one table to another table: Merging the tables. By adding table name into field for other table. By table join based on common fields in both tables. By spatial join based on intersecting geometry.

By table join based on common fields in both tables.

What was the one major advance in GIS technology that the Canada Geographic Information System achieved in the 1960s?

Calculating areas

In situ data capture

Capture of georaphic data on ground/in study area

Ordinal data

Categorical data determines rank/position/order

Sources of data

Census Nearmap Openstreetmap Qspatial

Imagine you are a large multi-national organisation that needs to share consistent GIS technololgy, tools and data across the organisation. What one of the following types of GIS architecture would be most appropriate? Centralised server architecture Client-server architecture Desktop PCs sharing files on a central PC file server Stand-alone GIS desktop architecture

Centralised server architecture

Three possible coding strategies for raster cells

Centre cell Majority cell Proportion

3 types of possible coding strategies

Centre of cell, majority of cell, proportion of cell (e.g. 0.5 of the cell is a certain colour then 0.5 will be recorded)

A vertical profile can be produced to show which of the following?

Change in elevation along a line

Tools when interested or not interested in a certain region

Clip Erase

Geographic Data Capture

Collection of geographic information from the real-world and representing that digitally in a GIS

Multicriteria Evaluation

Composed of many criteria with either a single objective in which you combine criteria together or multi objectives in which you prioritise or trade-off between objectives

As we apply increasing abstraction in developing a GIS database model we move to a more:

Computer-oriented representation

Identify two early innovations in the development of GIS technology and discuss why they were important.

Computerised map-measuring system allowed the calculation of area easier. Civilian satellites allowing for measuring of location and GPS (global positioning systems)

Logical consistency

Concerned with determining the faithfulness of the data structure for the data set. Typically involves spatial data inconsistencies.

Geographic and Projected coordinate systems, what are the different types?

Concerned with identifying where geographic features are on the Earth's surface Projected Coordinate Systems Transforms a three‐dimensional Geographic Coordinate System to flat coordinate system. In order to view geographic data as maps or on computer screens that are flat •Aerial photography and satellite imagery tend to be flat •Makes calculating distances, areas and angles much easier (otherwise need spherical trigonometry) •Small areas are essentially flat Different types: Plate Carrée Projection Maps latitudes and longitudes directly onto x and y coordinates Conformal, Equal Area, Equidistant, True Direction

How would you assess uncertainty in decision weights in an MCA problem? Conduct a sensitivity analysis Guess the weights Give up Assume all weights are equal

Conduct a Sensitivity Analysis

Universal Transverse Mercator

Conformal (minimal distortion of areas and distances within zones) Cylindrical projections 120 zones (60 N, 60S) Useful in 1 zone but distortions across

Identify three different types of projection and for each type of projection give one example of a GIS application where the projection would be appropriate.

Conformal - useful for navigation Equal area - useful for calculating areas Equidistant - useful for calculating distances

Uses of GIS

Conservation Planning, nuclear waste disposal (what is the the best location)

Primary ways we abstract the real‐world in a way that allows us to represent geographic information in a GIS

Continuous Fields Discrete Objects

Visual contrast

Contrast between sign & its background/adjacent signs Basis of seeing/distinguishing

Conventional vs GIS communication

Conventional = cartographer centred GIS = communicator centred

Conventional vs. GIS-based Communication

Conventional model: cartographer-centred GIS information communication: user-centred GIS maps not only provide information about location, distribution and patterns; it also provides real-time decision support, animation and simulation of spatial processes, predictive modelling, as well as integration with non-spatial statistical analysis. i.e. interactive mapping

When you are developing a spatial decision analysis system, how do you create criteria scores from spatial layers? Overlay layers and add Overlay layers and multiply Create logical rules to convert layers into criteria scores Average the values for each location

Create logical rules to convert layers into criteria scores

Buffers

Creates new polygon using buffer within a specified distance of feature, Helpful for roads or schools or protected areas

Discuss the similarities and differences between a digital terrain model and a digital surface model.

DTM is a bare-earth terrain surface created using ground returns only whereas DSM first return surface that represents a "shrink-wrapped" surface of the earth, including buildings, trees and other obstructions

Types of SQL Statements

Data Definition Language (DDL) create alter and delete data create table, create index (modify database structure) example: CREATE TABLE my_table ( my_field1 INT, my_field2 VARCHAR (50) my_field3 DATE NOT NULL, PRIMARY KEY (my_field1, my_field2) Data Manipulation Language (DML) retrieve and manipulate data within the tables SELECT,UPDATE,DELETE,INSERT

1990s GIS characteristics

Data collection and encoding was important (e.g., Ordnance Survey digital map creation) Little or no interaction among raster and vector data models (most GIS software considered one or the other) Modelling usually conducted outside of GIS, so GIS often just used for mapping Software often inaccessible to non-experts (command line driven software)

Which of these is NOT required for data in relational tables:

Data is organised and identified by sequential row number

Metadata

Data which tells you about the information in a data set. Should contain how, when, where data was collected scale coordinate system data quality and accuracy

Describing the components of the GeoWeb

Design Analysis Evaluate and compare urban design strategies quantitatively, according to measures such as: land use type density building height floor area ratio Use of "shape grammars" Performance Analysis Analyse and parametrise planning designs according to: Overshadowing View corridors Zoning regulation compliance Traffic gravity analysis Solar potential of buildings Greenspace Visualise and quantify the value of different types of green spaces Incorporate the benefits green spaces when evaluating current and future urban patterns as an explicit trade-off Property Values Calculate the visual range (of landscape views, sites of interest), sunlight exposure of individual apartments, offices or rooms within the building Accurately assess real-estate value Cost Estimation Calculate and compare against building performance criteria Energy/water consumption Construction waste Embodied energy Estimate building costs according to construction components

Types of GIS Architecture

Desktop - StandAlone GIS on PCs each with own files Client-Server - PCs connecting to DBMS via LAN or WAN Desktop Sharing files (Centralised Desktop) - Desktop GIS on PCs sharing files on a PC file server over a LAN Centralised Server - PCs, Browsers, Devices, connected to GIS Server (connected to DBMS) via LAN, WAN or Web GeoWeb

An inconsistent 3D geometry refers to which one of the following? a. The inconsistency between vector and raster data. b. The geometric correction that you have to apply to satellite imagery c. Different distances between adjacent grid elements d. Distance distortion when you re-project a data set

Different distances between adjacent grid elements

An inconsistent 3D geometry refers to which one of the following? a. Distance distortion when you re-project a data set b. Different distances between adjacent grid elements c. The geometric correction that you have to apply to satellite imagery d. The inconsistency between vector and raster data.

Different distances between adjacent grid elements

Primary and Secondary Data Capture for Raster Data Models

Digital remote sensing images Digital aerial photographs Scanned maps DEMs from maps

Primary raster data captue

Digital remote sensing images Digital aerial photographs

When you construct relationships between criteria values and standardised scores in a decision analysis you need to consider: (1) directionality, (2) shape, and (3) thresholds. Describe what each of these three considerations mean, using diagrams where appropriate.

Directionality is it a positive or negative relationship, shape (is too much of it bad, a little bad and the middle bad?), at what level or threshold (normally arbitrary) does the relationship change and therefore the score.

Explain, using examples, how vector analysis operations can be applied to aggregate and disaggregate spatial data.

Disaggregate Clip creates a new feature class from a larger feature class. Example: exclude the walks of a building from its area Erase to cut out part of a feature class. Example: exclude the kitchen from the area of a house Intersect: builds new feature class from the intersecting features common in both feature classes (AND function). Example: determine the parts of cyprus that is also turkish controlled. Aggregate: Dissolve where geometry is merged and new output feature is created, Examples: All polygons related to Toowoomba merged Spatial join to relate features based on spatial relationships e.g. intersect, contains or cross the sum of shops from shopping centres Union tool both aggregated and disaggregated by building a new feature class by combining the features and attributes of input feature classes. The combining of 2 school districts, that also overlap.

Positive questions

Discovery, advancement of science. E.g. where is global warming having largest impact.

Google's KML enables which one of the following?

Displaying Georeferenced information in a web browser

What operation is used to summarise features while also aggregating the spatial geometry to output features

Dissolve

What operation is used to summarise features while also aggregating the spatial geometry to output features. Correct Dissolve Summarize Overlay union Calculate geometry

Dissolve

Which one of the following is NOT a topological relationship?

Distance

Which one of the following is not a topological relationship? Adjacency Containment Distance Intersection

Distance

What map algebra operation is used to analyse a categorical raster (i.e. land use raster) to show the number of number of different categories (i.e. unique land use values) Maximum Diversity Majority Minority

Diversity

Disaggregation

Divide data to analyse data relations Either by duplicating or apportioning

Which one of the following questions would you NOT need GIS technology to answer?

Does solar power reduce carbon emissions?

Map bias

Drawn according to dominant philosophies & paradigms of the time Map projection, human errors & data accuracy

Advantages of vector

Easier to represent distinct features Can store more complex data

Legibility

Easy to understand, read Simple often best

Modifiable Areal Unit Problem

Effect of geographic unit size and shape on geographic patterns. Correlations between data may change depending on the spatial scale used to aggregate data.

Passive remote sensing

Energy comes from the sun. e.g. Landsat satellite - medium spatial & temporal resolutions but large coverage.

EAM

Entity Attribute Modelling

ERM

Entity Relationship Modeling aka Entity Attribute Modeling (EAM) identification of entities identification of relations between entities identification of attributes of entities derivation of tables

Ways to check data capture errors

Error Matrix Using topology to correct logical inconsistencies

A DEM can be modified by adding breaklines, such as streams, roads, ridgelines and shorelines to define the surface discontinuities. True/False?

False

All Surface analysis operations—Contour, Slope, Aspect, Hillshade, and Viewshed—can use rasters or TINs as input to generate another surface feature data as rasters. T/F?

False

Buffering cell data for a building footprint will calculate buffer distances from the center cell of the building pixels.

False

In GIS, information communication is based on a cartographer-centred model.

False

In GIS, information communication is based on a cartographer-centred model. True/False?

False

The best classification method for mapping differences in values from the average is the natural breaks method. T/F?

False

The classification of data can always help reveal meaningful patterns in a complex dataset. True or False?

False

The current development trajectory for GIS provides many advantages with few disadvantages. Is this statement true or false?

False

The statement 'Maps are true representation of the real world' always hold true.

False

Ture or False: Given the digital nature of GIS maps, it is generally OK to depend on the default setting of the GIS program when producing a map.

False

You are analysing census features with other features, which of these operations CANNOT be performed with a query 'select by location' operation:

Find the nearest census feature to a given police station feature

Brief history of GIS

First GIS was the Canada Geographic Information System, designed in the mid-1960s as a computerised map-measuring system (resulted in major advances for calculating area) Dual Independent Map Encoding (DIME) developed by the US Bureau of the Census to map US streets for the 1970 census Led to more efficient digital representation of streets which was a key technical advance Led to Odyssey software in the 1970s First digital map in 1973 (UK Experimental Cartography Unit) All of Britain not mapped digitally until 1995 though Remote Sensing: Source of technology and data. First military satellites in 1950s and first civilian satellites in 1970s. Led to uniform systems for measuring location and Global Positioning Systems 1980s onwards Explosion of commercially available software as costs of hardware and software fall First commercially available GIS software was ArcInfo(1981)

overlay analysis: raster (map algebra)

Forest and Water overlay: for intersect: multiply the two grids for identity: add two grids

Stream mode of manual digitising

GIS automatically creates points & you move cursor around outline of object to be digitised Better for complex shapes but may create more points which aren't necessary

2000s GIS characteristics

GIS became commonplace in people's everyday lives (e.g., navigation, online map searches, etc.) Remote sensing became a major source of data Modelling now possible within GIS, but still based around raster and vector data models and 3rd and 4th dimensions still not well dealt with (but this is changing fast) Integration of multi-media (e.g., Google Earth) and GPS into GIS occurred

Primary and Secondary Data Capture for Vector Data Models

GPS measurements Survey measurements Topographic surveys Toponymy (placename) data sets from atlases

Vector in situ data capture

GPS (based on signals from satellites of known positions) Ground surveying (measuring angles & distances from known points) Digitising (using digitising table; manual on screen digitising)

The earth's gravitational field is important for defining which one of the following?

Geoid

Topology and example use

Geometric characteristics that do not change under transformations Important for analysis, e.g., network analysis

GE

Google Earth, 2005 people map hacking and map mashups aren't by cartographers in the traditional, academic sense but by programmers intrigued by mapping's potential to deliver meaningful information open source mapping means that cartographer is in the hands of the users, not just GIScientists or cartographers and only works when people have access to them

Primary vector data capture

Gps measurements Survey measurements

Hierarchical structure

Graphic structure needed to separate characteristics and portray likenesses/interrelationships

Raster data model

Grid cells which contain info about spatial locations Most useful for continuous fields Attributes recorded by assigning each cell a single value based on majority feature in the cell Ty

Types of DBMS models

Hierarchical Network Relational-RDBMS

Spatial resolution

How much spatial area is represented in one unit

Temporal resolution

How often data is captured i.e. more frequent data capture = greater resolution

Nominal data

Identify one entity from another

Georeferencing

Identifying and matching geographic data to its location in real life. Georeferenced locations should be unique, constant through time. Use control points to match features to real world.

Cloud platform GIS can provide which one of the following benefits? a. Improved scalability b. Ensure all data are secure c. New data capture technology d. Better data collection

Improved scalability

Briefly discuss the different types of database relationships and explain the differences between the "relate" and "join" operations.

In relational databases, relationships include one to one relationships, one to many, many to one and many to many relationship. Join operations are based on joining or merging one field, tables or layers of information to other tables or layers, based on a common field. It is a one to one relationship Relate normally is a function that relates a layer to another layer or table based on a field value, doesn't necessarily require a table amendment like join operations, instead you click on the field to see the related fields. Is an example of a one to many relationship

Functions of GIS map

Information presenter Data store = geodatabases, data warehouses Data carriers = optical media, computer networks

Definitions of GIS

Integrates hardware, software, and data for capturing, managing, analysing, and displaying all forms of geographically referenced information A complex of software, hardware, data, people/institutions, activities/procedures and networks

Continuous field abstraction

Interval or ratio data Where values vary continually over space

In Situ Data Collection

Involves the capture of geographic data on the ground. Can be both vector data (e.g., surveying and GPS) and raster (e.g., scanning, digitising)

Location based services

Is a device that knows where it is and is capable of modifying the information it provides based on that location and usually across the internet (e.g., GPS, mobile phones, mobile GIS)

Briefly describe one example application of a location-based service and identify the one key reason for using a location-based service in this example.

Is a device that knows where it is and is capable of modifying the information it provides based on that location and usually across the internet An example is a mobile phone, an example of the application of location based service is in an emergency, emergency services maybe able to pinpoint your location based on your mobile phone. Meaning you maybe able to make the call without needing to be crystal clear regarding your location.

Explain what LiDAR is, and how LiDAR data can be used to create a Digital Terrain Model (DTM).

Is an active data capture. Where capture is based on a laser and receiver that records return times at points across a band. Current systems normally provided both first and last returns. Return times allow elevations to be estimated which can then be feed into to determine a digital terrain model however it is worth noting the last return results is required to determine the terrain model

What is geographical data? Identify THREE (3) different methods for collecting primary data, and THREE (3) different secondary data sources for GIS use.

Is any data or information that has a spatial referenced component 3 methods of primary data, LiDAR, Satellite, GPS measurements 3 methods of secondary data scanned maps, Government census data and topographic surveys

Attribute accuracy

Is the attribute correctly labelled/named? Ability to accurately identify objects on earth's surface.

Slope

Is the change in elevation (a rise) with a change in horizontal position (a run) at a surface location;

Viewshed Analysis

Is the portion of the land surface that is visible from one or more viewpoints. Can use DEM or TIN

Watershed Analysis

Is the upslope area contributing flow to a given location. Mainly use DEM

They say that GIS decision analysis can help with triple bottom line decision-making. This means: It can check which of three alternatives are compatible with our bottom line (ie profitable) It can find alternatives which meet environmental, political and economic objectives It can find alternatives which meet environmental, spiritual and economic objectives It can find alternatives which meet environmental, social and economic objectives

It can find alternatives which meet environmental, social and economic objectives

Common criticisms of the feature overlay operation in GIS are: It can only handle Boolean maps, i.e. with yes/no values The result loses the associated attributes for input layers It only permits overlay between features of same spatial dimension It cannot assess or account for any attribute or spatial variability in the input layers

It cannot assess or account for any attribute or spatial variability in the input layers

The main advantage of a total stattion over a standard theodolite is which one of the following? It is cheaper It is legally allowed to be used in more countries It has an electronic distance measuring device It contains a GPS

It has an electronic distance measuring device

Which one of the following is an important reason to include metadata with geographic data? It makes data sets have greater positional accuracy It is required by law It is part of the vector data model It is critical information to aid the sharing of data

It is critical information to aid the sharing of data

Which one of the following best describes the main advantage of object-based vector models? It is cheap It will work on Macs and PCs It is efficient because it is able to store all objects in a single system It is the only way to represent shapefiles

It is efficient because it is able to store all objects in a single system

Remote sensing has benefited the development of GIS in which two of the following ways? It provided new ways of visualising data It provided technology and data It provided uniform ways of measuring location It helped to develp new computer languages

It provided technology and data It provided uniform ways of measuring location

How GPS works

Known as trilateration (require 3 satellites to get approximate location, 4 to get an accurate location - allows time correction)

Briefly describe three key issues that are likely to be important future challenges for GIS. Say what they are and explain why they are likely to be challenging.

Lack of GIS training, complex analysis techniques are now also becoming increasingly available, within training inaccuracies and misinterpretation is more likely Data standards and specifications the shift from centrally (government) controlled data portals to the diffuse GeoWeb makes the implementation of standards problematic, could reduce the standard of GIS information Privacy and Data ownership issues with vast amounts of spatially referenced information freely available on the web, privacy and data ownerships issues will become more important. Who owns the data and what data can you keep

Describe three key issues that are likely to be important future challenges for GIS. Say what they are and explain why they are likely to be challenging.

Lack of GIS training, complex analysis techniques are now also becoming increasingly available, within training inaccuracies and misinterpretation is more likely Data standards and specifications the shift from centrally (government) controlled data portals to the diffuse GeoWeb makes the implementation of standards problematic, could reduce the standard of GIS information Privacy and Data ownership issues with vast amounts of spatially referenced information freely available on the web, privacy and data ownerships issues will become more important. Who owns the data and what data can you keep

Application of Raster Analysis

Land Use Analysis Terrain and Hydrological Analysis Environmental Analysis

Give an example of a decision problem, and explain how a GIS based multicriteria analysis approach can be applied to address this problem.

Land suitability of an area to be set aside for as a protected area.

Defining and interpreting Criteria

Land values that measure achievement for a desired state of the world you want to achieve.

Principles of Map Design

Legibility - easy to read and understand Visual contrast - the way a sign contrasts with its background and adjacent signs - Contrast is the basis of seeing Figure-ground organisation - allow user to focus on the figure rather than ground Hierarchical structure - graphic structuring is needed to separate meaningful characteristics and portray likenesses, differences and interrelationships

Map design principles

Legibility Visual Contrast Figure-ground organisation Hierarchical structure

Data Representation types

Line Symbol Maps e.g. Flow-line Maps: Portrays movement between places, with arrowheads depicting direction Isoline Maps Dot Maps A dot represents a given quantity of the mapped item Area Symbol Maps Maps using area symbols can show differences in kind or Differences in quantity Proportional Symbol Maps Choropleth Mapping - Involves colouring geographic areas to represent categories of rates or densities - also called graduated colour map 3D Mapping

Limitations of Geographical Decision Analysis

Linearity of criteria, independence of criteria, especially for the additive rule Criteria and weights is subjective and sensitive Ecological fallacy

Types of questions you can answer with GIS

Location Pattern Trends Conditions Implications

What happens if you use a wrong reference system?

Location appears differently, you can end up in the wrong location

Types of Questions for GIS

Location. Where is the nearest shop? Patterns. Where do high concentrations of students live? Trends. Where are glaciers retreating in the European Alps? Conditions. Where is the flat land within 500 m of the highway? Implications. If we build a theme park here, what will be the effect on traffic flows?

Point mode of manual digitising

Manually creates points & join by lines

GIS views

Map view, database view (geodatabase), model view

Suppose you are a national park manager, which one of the following would you most likely use GIS for? Developing guided tours for visitors Conducting surveys to identify rare plants Creating newsletters Mapping where weeds occur to prioritise weed eradication programs

Mapping where weeds occur to prioritise weed eradication programs

Types of products that the GeoWeb enables

Mashups take data or online geospatial services from multiple sources and combine them into a single integrated tool Cloud Platform GIS Citizen science and more availability to the public

A Geoid is used to measure which one of the following?

Mean sea level

GIS questions and possible solutions Which is the longest ski piste in Happy Valley? What is the total area of forestry in the valley? How many luxury hotels are there in the valley? Where are the luxury hotels with less than 20 bedrooms? Which hotels are within 200 m of a main road? In which land use types are the meteorological stations located? Which roads should I use for a scenic forest drive? What is the predominant land use type in the Happy Valley resort? Where could a new ski piste be located? What is the predicted snowfall for the new ski piste?What are the slope and aspect of the new ski piste? From where will the new ski piste be visible?

Measurement of length or query of attribute database if length is included area measurement or reclassification of foresty map, then area calculation attribute (aspatial) data query attribute query followed by spatial query or Combinatory AND query buffering, then point-inpolygon overlay, then query or proximity analysis, then reclassification, then point-in-polygon overlay and query point-in-polygon overlay line-in-polygon overlay polygon-on-polygon overlay (identity) then query a map algebra overlay, depending on siting criteria selected interpolation, then overlay 3D analysis, slope and aspect calculation 3D analysis-visibility analysis

map projections?

Mercator projection is racist: over-values the white man, distorts the world to advantage of colonial masters of the time all previous population maps were deficient because they assumed that places existed naturally before the act of mapping, with existing political boundaries. a truer sense of place is created by the act of mapping tiself. maps were applied political economy, and were no less political for being applied

Which of these is INCORRECT operator for summary statistic with categorical attribute data

Minimum

Completeness

Missing data. Holes in data, unclassified areas, & any compilation procedures that may have caused data to be eliminated.

How do conventional and GIS communication differ

Mode, objective, scope of communication, level of interaction between user and map GIS not only provides info about locations and geo patterns, also decision support, animation, simulation, predictive modelling, integration with non-spatial stats analysis

Describe scale issues, what is MAUP? The differences between scale and extent? Explain how it relates to the issue of scale in GIS. Give one reason why it is an important consideration for data capture. Suggest one method that can be used to assess the effects.

Modifiable Areal Unit Problem - The effect of geographic unit size and shape on geographic patterns • The scale effect •The zoning effect Is a problem when point-based measures of spatial phenomena are aggregated or disaggregated into different zones or scales. Can produce inaccurate assumptions and conclusions regarding a zone or area. Could perform sensitivity analysis on the scales and zones.

MAUP

Modifiable areal unit problem

Advantages of raster data

Much data comes in this form Good for continuous features

You are given a set of data on the average annual household income at each suburbs in Southeast Queensland. If you are to produce a choropleth map showing the spatial distribution of household income across those suburbs, which data classification method would you NOT use? Answers: Natural breaks Equal intervals Defined equal intervals Correct Quantile breaks

Natural breaks

What GIS tool would you use to calculate the shortest distance between river segments (line features) and landmarks (point features)

Near calculates the distance from one feature to the nearest other feature

Map elements used selectively for effective communication

Neat line Locator map Inset map Index map

What raster operation may be used to compute surface variation (roughness) across elevation raster:

Neighborhood standard deviation

Describe what kind of raster data will be generated using a Neighbourhood (focal) operation in GIS. Give an example where you will use a neighbourhood operation, and specify how many raster data layer you will need to run this operation.

Neighbour cells is the function of each cell as focal cells and its surrounding cells based on spatial relationship. It maybe you are looking for the most appropriate location for a health clinic, so you might only be able to build at certain locations or cells and then you would allocate that as your focal cell. Then you would work out which neighbourhood is most needing of a health clinic. You might use distances from other clinics as one layer and then transport mobility of the population in the neighbourhood and then you might add up the layers and work out the average for each focal cell and compare and work out which is the best location

A useful topology for roads is which one of the following?

Network

Levels of Measurement

Nominal Scale: identify one entity from another, e.g., types of land use; soil types,etc. Ordinal Scale: categorical data that determines position, rank or order e.g.,SeCat Interval Scale: Values are on a linear calibrated scale but not relative to a zero point in time and space, e.g. pH value scale, temperature scales in C & F, IQ score Ratio Scale: values are derived relative to a fixed zero point on a linear scale

Discrete object abstraction

Nominal or ordinal data Discrete entities Delineate boundaries

Given a set of census features, which spatial analysis operation avoids the ecological fallacy problem (also called modifiable area unit problem) for interpreting population values of output features: Dissolve features on a region attribute and ouput statistical average of census population Union features with another set of arbitrary polygon features, i.e. with school districts Dissolve features on a region attribute and ouput statistical minimum of census population None of the above avoid ecological fallacy problem.

None of the above avoid ecological fallacy problem

Classes of Questions for GIS

Normative (Practical or Decision-making/Design Applications).Where to site a nuclear power plant? Positive (Discovery or the Advancement of Science). Where is global warming having the greatest impact on natural systems?

Importance of Cardinality

One-One: An instance of an entity relates to a unique instance of other entity. (One parcel has one owner) One-Many: An instance of an entity relates to many instances of an other (and visa-versa for many-to-one). One parcel has many owners or Many parcels have one owner Many-Many: Many instances of one entity relate to multiple instances of another 3 tables required to represent data in DBMS, i.e. link table is needed (Many parcels have many owners)

The main difference between narrow and broad definitions of GIS is that broad definitions usually include which one of the following components that narrow definitions do not include? Data Software Procedures People

People

Which one of the following best describes why humanware is one of the most important components of a GIS? People are needed to perform GIS analyses and to interpret the results Humans are required to build digital networks Humans are necessary to service satellites GIS is a human invention and wouldn't exist without them

People are needed to perform GIS analyses and to interpret the results

5 Step Data Collection Process

Planning Preparation Digitising/transfer Editing/improvement Evaluation

Five Step Data Collection Process

Planning -> Preparation -> Digitizing/Transfer -> Editing/Improvement -> Evaluation

Vector data model

Points, lines, polygons Most useful for discrete objects What is used to represent an object depends on level of abstraction/scale of map

Buffering creates which of the following types of features? A. Polygons B. Point C Polygon D. any of the above

Polygons

Which of these is NOT a valid feature overlay operation: Polygons overlay intersect with points Polygons overlay intersect with lines Polygons overlay union with lines Lines overlay intersect with lines.

Polygons overlay union with lines

Imagine that you are implementing a data collection program to identify the location of lamp posts along a section of road using a GPS. What one of the following types of accuracy should you be most concerned with?

Positional accuracy

4 types of measurement error

Positional accuracy Attribute accuracy Logical consistency Completeness

Why GIS matters

Powerful visualisations Analysis of spatial data Everything has a spatial location Many spatial problems difficult to solve by hand Spatial analysis requires many specialised tools which GIS technology supplies

Normative questions

Practical, decision-making. e.g. where to place new power plant

True direction (azithumal)

Preserves direction with respect to centre Useful for navigation

Data collection using a GPS is a form of ......... vector data capture.

Primary... in-situ

Pro and Cons of Geographical Decision Analysis

Pros: Rational decision approach Helps to structure a problem Links goals and impacts to decisions Trade-off alternative choices Makes best recommendation Cons: Does not make final decision There are many assumptions in derivations: scale of criteria attributes and independence of criteria Aggregation may blur a bad decision

Where can you get data for spatial layers to populate criteria?

Publically available data sets (eg government data) Published data (eg maps in journal articles) Expert opinion Community mapping

Which data classification method can be used to divide the total number of observations into the desired number of classes, with each class having equal number of observations? Defined equal intervals Natural breaks Quantile breaks Equal intervals

Quantile Breaks

You are given a set of data on the average annual household income at each suburbs in Southeast Queensland. If you are to produce a choropleth map showing the spatial distribution of household income across those suburbs, which data classification method would you NOT use? Quantile breaks Natural breaks Defined equal intervals Equal intervals

Quantile Breaks

You are given a set of data on the average annual household income at each suburbs in Southeast Queensland. If you are to produce a choropleth map showing the spatial distribution of household income across those suburbs, which data classification method would you NOT use?

Quantile breaks

Which two of the following are suitable problems to solve using geographical decision analysis?

Ranking suitability of sites for nuclear waste storage

Which two of the following are suitable problems to solve using geographical decision analysis? Ranking suitability of sites for nuclear waste storage The selection of the most appropriate type of fencing for a property Designing roads or railways Comparing greenhouse gas abatement strategies Mapping suitable land uses for a region

Ranking suitability of sites for nuclear waste storage Mapping suitable land uses for a region

How vector and raster data models are represented digitally (including topology)

Raster • Grid cells • Most useful for representing continuous fields • majority feature (attribute) in the cell • Cell values are represented as numbers within a database Vector • Points (trees, poles, fire, plugs, airport), lines (stream, streets, sewers) or polygons (areas, land parcels, cities, counties) • Most useful for representing discrete objects

Pros and Cons of Vector and Raster

Raster is faster but vector is corrector Raster: - location is referenced by a grid cell in a rectangular array (matrix) - attribute is represented as a single value for that cell - much data comes in this form • images from remote sensing (LANDSAT,SPOT) • scanned maps • elevation or DEM data -best for continuous features: • elevation • temperature • soil type • land use Vector data model - location referenced by x,y coordinates, which can be linked to form lines and polygons - attributes referenced through unique ID number to tables - much data comes in this form • census data (tabular) -best for features with discrete boundaries • property lines • political boundaries • transportation

Identify and discuss the advantages and disadvantages of using vector and raster data for spatial analysis/modelling.

Raster is good for data that comes from • images from remote sensing (LANDSAT,SPOT) • scanned maps • elevation or DEM data -best for continuous features Vector is good for data that comes from census data (tabular) -best for features with discrete boundaries Raster is often good for calculations and is normally faster to model whereas vector is more often more accurate in its modelling but normally takes more time to collate and modelling

One advantage of mobile GIS is which one of the following?

Real time updating of GIS data from the field

Type of neighborhood

Rectangle, Wedge, Circle, Annulus

What is a relational database? Describe what a primary key and a foreign key is in a relational DBMS.

Relational databases allow linked tables to avoid repetition of information across rows. A primary key columns that uniquely identify or specify a row, e.g. lot number or ID number A foreign key is a column or group of columns in a relational database table that provides a link between data in two tables

Active remote sensing

Remote sensor has own energy source. e.g. LiDAR - based on a laser which projects onto earth surface, times return time & infers distance useful for elevation; high resolution, precision and accuracy

Ex-situ data capture, the 2 different types and examples

Remotely Sensed Data Capture Satellite imagery and aerial photography mainly Resolution (spatial, spectral, temporal and radiometric) Passive (i.e. using the sun e.g., aerial photography) and active (i.e. using the light e.g., radar) Landsat (Passive - Satelite) Thermal Imagery (Passive) LiDAR(Active - Laser scanner)

2 types of scale

Resolution (size of spatial unit of measurement) Extent (size of study area)

Which of these is NOT stored in a geodatabase:

Results from a table query

Which of the following data is not required to develop a 3D city model? Digital Terrain Model (DTM) Building description Road signage Building heights

Road Sinage

When you've populated your GIS MCA system, how would you first improve its validity?

Run the system for known situations to make sure it gives the best answers, and modify it till it does

When you've populated your GIS MCA system, how would you first improve its validity? Use it to make the decision and then evaluate whether it was a good choice and feed the results into the criteria functions Run the system for known situations to make sure it gives the best answers, and modify it till it does Get the stakeholders to change their weighting preferences if it's not choosing the right answer Alter the GIS data layers until it produces acceptable results

Run the system for known situations to make sure it gives the best answers, and modify it till it does

Map elements on all maps

Scale Direction Legend Lineage

Conformal projections

Scale is preserved & attempts to preserve shapes of features Useful for navigation

Secondary raster data capture

Scanned maps DEMs from maps

In situ raster capture

Scanning of maps Aerial photography

Differences of secondary and primary data capture

Secondary are non-digital data capture that is then converted to digital, where as primary is data that is digital with geographical information to integrate into GIS.

Topological Relationships

See image

Radiometric resolution

Sensitivity by which reflected radiation is measured

Spectral resolution

Sensor detects energy released at a given wavelength - resolution at which wavelengths are measured. i.e. low resolution = wide, has few bands. high resolution = narrow, more bands.

If you are mapping a vast flat area and would like to emphasize slight elevation change in the landscape using 3D visualisation in ArcScene. What is the best way to do so?

Set a vertical exaggeration

Mercator Projection

Shape Preserving - A true conformal cylindrical map projection, the Mercator projection is particularly useful for navigation because it maintains accurate direction. Mercator projections are famous for their distortion in area that makes land masses at the poles appear oversized.

Aggregation

Simplify and summarise data to reveal overall trend Can be done via dissolve, spatial join (based on topographic relationship, join rules (between on features)

List the six components of GIS and, for each one, briefly describe what role it plays.

Software is the set of instructions, data or programs that tell hardware how to work Hardware is the physical equipment in order to store data and use software Data is the bases and store of information inclusive of spatial information, stored on hardware or collected and stored on hardware People Procedures Networks

Consider the 3D city model of Adelaide shown below: Describe three types of questions that you could address using this model and explain how the 3D city model helps you do this.

Solar potential of buildings by calculating overshadowing More accurately assess real-estate value by calculating the visual range (of landscape views, sites of interest), sunlight exposure of individual apartments, offices or rooms within the building Evaluate and compare urban design strategies by closely reviewing land use type, density, building height, floor area ratio Overall, they allow "for visually integrating heterogeneous geo information within a single framework and, therefore, create and manage complex urban information spaces."

What are the 2 types of attribute data

Spatial attributes (locations) Non‐spatial attributes

4 types of resolution in remotely sensed data capture

Spatial resolution Temporal resolution Spectral resolution Radiometric resolution

RDBM tables

Spatial: points, lines, polygons Attribute: hotels, visitors, travel companies

Thematic maps show: Specific topics and their geographic relationships and distributions Temperature of a region as discrete classifications across the landscape How land is divided into land boundaries and parcels The relationship between the physical characteristics of land in an area to the built environment

Specific topics and their geographic relationships and distributions

Database Structures

Spreadsheet (i.e. Excel), Flatfile (i.e. Shapefile), DBMS (i.e. MS Access, Oracle)

which of these is NOT considered a local raster operation.

Step across each focal cell in raster computing the average for its nearest cells.

Describe three important requirements for allowing the sharing of geographic data.

Strict metadata standards (requiring data is have scale, coordinate system, data quality and accuracy, and who, how, when and where is the data collected) Standard data formats for transferability among platforms Data sharing agreements (legal issues) to avoid legal issue regarding who owns the information

GIS-DBMS roles

System GIS-->DBMS-->Data GIS task: loading data, editing, visualizing, mapping, analyzing DBMS task: storing, indexing, updating, security, querying

Types of Data Models Used for Terrain Analysis

TIN Triangulated Irregular Network and DEM Digital Elevation Model

Jenks Natural Breaks Classification method seeks to increase the variance between classes and minimise the variance within classes.

TRUE

Which one of the following is not a relevant concept of resolution for remote sensing? Temperature Spectral Spatial Temporal

Temperature

When you use a decision support system such as spatial MCA how is the decision made? The GIS picks the best alternatives The trade-off between stakeholders picks which one wins The sensitivity analysis shows there's no reliably best option so we do nothing Those entrusted with the power to make the decision will make it and may not take into account the MCA results

The GIS picks the best alternatives

Which one of the following describes the ecological fallacy? The belief that all observations within a given area have the same values The belief that ecological systems are simpler than physical systems The idea that the extent of a study area is important The idea that feedbacks complicate the interpretation of geographic data

The belief that all observations within a given area have the same values

Normalized digital surface model nDSM

The difference between the DSM and DTM surfaces, or a DSM normalized to the bare-earth surface. Can be used to calculate the height of buildings, trees, or other features

Positional accuracy

The expected difference in the measure geographic location of an entity from its true ground position. 2 types: Absolute (with respect to a coordinate system) Relative (with respect to position of geographic entities relative to each other)

What information is stored in a geodatabase as opposed to being saved within a map document.

The geometry for features.

What information is stored in a geodatabase as opposed to being saved within a map document. Cartographic symbolisation for rendering features. The geometry for features. Display scales used for rendering features. Layer definition queries.

The geometry for features.

Explain how GIS-based information communication is different from the conventional cartographic communication model?

The goal of conventional cartographic communication is to communicate the spatial information portrayed on the map as effectively and efficiently as possible Whereas GIS is user-centred, GIS maps not only provide information about location, distribution and patterns; it also provides real-time decision support, animation and simulation of spatial processes, predictive modelling, as well as integration with non-spatial statistical analysis.

The exact shape of the earth (an ellipsoid) is important for calculating Geodetic latitude because of which one of the following? The shape of the earth influences the angle that a line drawn perpendicular to the earth's surface makes with the equator The earth changes shape over time The volume of the earth depends on its shape The shape of the earth must be known to project it onto a flat surface

The shape of the earth influences the angle that a line drawn perpendicular to the earth's surface makes with the equator

Assume that Site A has an aspect value of 0 and Site B has an aspect value of -1. Which of the following statements is true? The slope at Site A is steeper than at Site B The slope at Site B is steeper than at Site A The slopes at Site A and Site B are equal None of the above statements is necessarily true

The slope at Site A is steeper than at Site B

Scale

The spatial scale of digital geographic data consists of extent and resolution

What are the challenges in representing the world in a GIS?

The world is an infinitely complex place. A GIS cannot represent all of this infinite complexity

When calculating slope, if there is a cell in the neighbourhood with NoData, which one of the following applies?

The z-value of the central cell will be assigned to the NoData cell

When calculating slope for a cell at the edge of the raster, at least three neighbouring cells will be outside the raster's extent and therefore have NoData. How would you calculate the cell's slope?

The z-value of the central cell will be assigned to the NoData cells

Sensitivity Analysis

There is no way to check correctness of a decision but can sheck how strongly results hold given methodology. Will methodology change the solution

A group of cells in a raster is considered as a zone if:

They have the same integer valued identifier

Map elements sensitive to context

Title Projection Cartographer Date of production

Data standards are required for which one of the following?

To ensure the ability to share data

Secondary vector data capture

Topographic surveys Toponymy data sets from atlases

3-D city model components are typically constructed at various levels of detail (LOD) to provide components at different resolutions and at different levels of abstraction.

True

3D GIS can be used to visualise the relationship between two or more data variables. True/False?

True

Choropleth mapping involves colouring geographic areas to represent categories of rates or densities. True False

True

Jenks Natural Breaks Classification method seeks to increase the variance between classes and minimise the variance within classes. T/F?

True

Most raster operation accept one or more rasters as input and generate one or several rasters as the result

True

Most raster operation accept one or more rasters as input and generate one or several rasters as the result. True or False?

True

Quantile breaks classify data by dividing the total number of observations equally into the desired number of classes. True False

True

You can share your 3D city model created in CityEngine as an interactive Web Scene to your ArcGIS online account. T/F?

True

A 3D city model can be used to analyse and compare different design strategies. T/F?

Ture

Spatial Queries

Two fundamental ways to do spatial queries: 1.Coordinate: distance (i.e. within), within coordinate extent (window) ▫Are within a distance of 2.Relationship: topological relations (i.e. contained in, overlap, etc.) Intersect Completely contain Are completely within Have their centerin Share a line segment with Touch the boundary of Are identical to Are crossed by the outline of Contain Are contained by

Which of the following data cannot be generated from LiDAR data?

Type of trees and their heights

URISA GIS code of ethics

URISA is a multi disciplinary geospatial organization that provides rofessional education and raining, a vibrant and connected community, advocacy for geospatial challenges and issues, and essential resources. URISA fosters excellence in GIs and engages geospatial professionals throughout their careers obligations to society: do the best work possible (be objective, provide full clear accurate info) contribute to the community to the extent possible, feasible, and advisable speak out about issues obligations to employers and funders deliver quality work (stay up to date, document work) have a professional relationship, be honest in representations respect the work of others, contribute to the discipline to the extent possible respect privacy, respect individuals

Spatial data overlays functions

Union: (OR function) builds new feature class by combining the features and attributes of input feature classes. Intersect: (AND function) builds new feature class from the intersecting features common in both feature classes Update tool: updates the attributes and geometry of an input feature class or layer by the update feature class or layer that they overlap. Clip tool: builds new feature class from input features overlying the clip feature, i.e. as a 'cookie cutter

The three tiers of a typical GIS architecture refer to which of the following three?

User interface Tools Database management

3 tiers of GIS architecture

User interface (presenttion) Tools (Business logic) Data management (data server)

Ratio

Values derived relative to a fixed/absolute 0 point `

Interval

Values on calibrated linear scale but not related to a 0 point e.g. pH value, IQ score

Overshoots are an example of an error that arises from which one of the following data

Vector digitising

Overshoots are an example of an error that arises from which one of the following data capture methods?

Vector digitising

3D Visualisation

Viewing a remotely sensed image draped over a terrain surface can often lead to greater understanding of the patterns in the image and how they relate to the shape of the earth's surface. Need DEM or TIN to provide the surface for 3D perspective views and 3D draping

3D Visualisation key terms

Viewing azimuth: direction from the observer to the surface, ranging from 0 to 360 degrees clockwise Viewing angle: the angle from the horizon to the altitude of the observer Viewing distance: distance between the viewer and the surface Z-scale(vertical exaggeration factor): the ratio between the vertical and horizontal scale

Describe what is involved in viewshed analysis. Give an example where you can use it. Identify the three critical parameters for computing a viewshed.

Viewshed is described as the portion of the land surface that is visible from one or more viewpoints. The analysis is to identify the land visible from one or more viewpoints, i.e. a light tower.

Identify a geographical problem that you would solve using GIS. Then answer the following questions: a) What geographic data would you need to solve the problem? b) How would you capture the primary data you need (if any), and/or from where would you collect the secondary data? c) What data model would you use and why?

Where to site a nuclear power plant in Queensland? a) population densities, Average wind direction and speed, tectonic plate position and earthquake history, proximity to major roads and electricity grid, and Waterways b) census data (secondary data), average wind direction and speed from meteorology services (secondary data), geological services (secondary data), road location information (secondary data), c) Raster converted to vector, as the

Challenges in representing real world

World is infinitely complex GIS can't represent infinite complexity

Given input A as the zonal raster and input B as the value raster below; what is the result of the operation for a zonal average:

Zone 1 = 3.0, Zone 2 = 3.0

What is a GIS data model? Describe the conceptual steps you would undertake to create a GIS data model.

a set of constructs for representing objects and processes in the digital environment of a computer. i.e. it allows the geographic features in real world locations to be digitally represented and stored in a database so that they can be abstractly presented in map form, and can also be worked with and manipulated to address some real world problems. Steps: 1. Plan 2. Prepare 3. Digitalising/Transfer (capture data) 4. Editing/Improvement 5. Evaluation Reality -> Conceptual Model -> Logical Model -> Physical Model

Data model

a set of expectations about the data (a template), spatial data models: vector and raster, attribute data model: tables (RDBMS)

raster: line-in-polygon

add the layers

raster: point-in-polygon

add the two data layers all cells in the raster are numbered

post-war cartography

adopted internalist ethics, but not externalist, thought mapping and politics relationship was bias, lies and exaggeration political geography emergence of Robinsonian cartography in part a reaction to the political uses of map by Nazis and Allies, call for more training, rigor, and rules

location-allocation modeling

allocation of resources by the modeling of supply and demand through a network match supply with demand requires movement of goods, people, information or serices through the network

Relational Database Management System

allows users to create, read, update, and delete data in a relational database

Interpolation

an estimation of a value within two known values in a sequence of values. Related to ecological fallacy

what is critique? a critical politics of truth

an examination of assumptions of a field of knowledge. understand and suggest alts to the categories of knowledge that we use. assumptions and familiar notions shape our knowledge.

what methods of data encoding are available?

analogue spatial data: manual digitizing automatic digitizing keycoding scanning digital spatial data: transfer data reformatting

Data analysis: basic first steps

any analysis should always start by examining the basic descriptive statistics (measures of central tendency like mean, mode, median), measures of dispersion (standard deviation) and by viewing graphic summaries of the data GIS analysis is no different

API

application programming interfaces define the way one piece of software connects up with another when these are open-source it means that independence developers can connect their software to others like Yahoo, Google, and Flickr

Metadata and Data sharing

are data about data and should, at least, contain information on: •How, when, where and who collected the data •Scale of data •Coordinate system •Data quality and accuracy Sharing of GIS data is becoming commonplace, but requires: •Strict metadata standards •Standard data formats for transferability among platforms •Data sharing agreements (legal issues)

Geodesic buffers

are those that account for the actual shape of the earth (an ellipsoid, or more properly, a geoid).

Differences in-situ and ex-situ data capture

attaching GPS collars to giraffes v Remotely sensed data capture - satellite images

how are paper maps digitized?

automatic or manual digitizing using various techniques and technology, or scanning

measurements in GIS

basic geographic questions: size of areas (forest stands), distance between features (forest stand to mill) (buffers around stream), length of features (length of hiking trail), shape of features (relation between area and perimeter), direction of features (orientation of slopes) how to measure length? straight-line distance (Pythagorean geometry) manhattan distance (grid, road network) proximity or buffer distance perimeters: sum of lengths of sides areas: sum of cells (R), formula (V) issues: length, perimeter, and area depends on the resolution of the data (in particular for raster data-cell size) units depend on the projection of the data for analysis, project data to common coordinate system for mapping 'projection on the fly' in ArcGIS is enough lat/long - easy positioning, but length or area measurement not intuitive

manual classification

boundaries set according to external criteria (income levels associated with poverty line, water quality standards) useful for identifying which regions need particular attention, which are doing well obscures data distribution

data transfer

buy or create is important Q many widely distributed sources of GI key catalogs include: geogratis, geobase, geography network, official government sources Question the data: what is the format? when was the data created? how often updated? what projectioN? what scale? any use restrictions? who did it? reliability?

data integration

can combine data in novel ways, creating new violations of privacy eg non spatial patient data could be linked with patient addresses, can use privacy preserving record linkage PPRL techniques to address this issue

vector: polygon-on-polygon overlay

can result in 3 different output maps depending on boolean operation performed UNION=OR IDENTITY=NOT INTERSECT=AND

Raster primary data capture

capture specifically for GIS use raster-remote sensing, satellites and aerial photograpy, passive and active sensors resolution is key consideration, spatial is at what resolution, spectral is at what wavelengths are being captured, temporal is what timeframe?

process of creating integrated GIS database: data stream model

collecting data from: maps (digitize), satellite data (scanning) digital data and tabular data (data transfer) and soft ideas (key coding) ALL lead to data capture-->editing/cleaning-->reprojection-->generalization-->edge-matching/rubber sheeting-->layering-->integrated GIS database

vector secondary data capture

collection of vector objects from maps, photographs, plans, etc digitizing: manual (using a 'puck' on an actual map), heads-up (on a computer screen) photogrammetry-the science and technology of making measurements from photographs, etc plane takes images along path with 60% overlap, same area from 2 different angles compare photographs to determine height of features can create 3D image using stereoscope

union

combine ALL features into new layer

Map Algebra

commonly used tool for local operations

secondary surfaces

computing slope and aspect from DEMs

proximity distance

concentric equidistant zones are established around the start point A. resulting image shows the shortest straight line distance from every point on the map (including end point B to the lcoation of interest (A) used in raster measurements

thiessen polygons

connect the points, draw perpendicular bisectors, connect the bisector lines, thiessen polygons delimit zones of influence (all points within the polygon are closer to the central point than to any other point exact method of interpolation that assumes that the values of unsampled locations are equal to the value of the nearest sampled point. local interpolator because global characteristics of the data set exert no influence over the interpolation process. abrupt method of interpolation as sharp boundaries are present between the interpolated polygons created by subdividing lines joining nearest neighbor points, drawing perpendicular bisectors through these lines, and then using these bisectors to assemble polygon edges.

bias

consistent error throughout the data set

Data Stream

creation of a clean digital database is the most important and time consuming task upon which the usefulness of the GIS depends the general consensus among the GIS community is that 60 to 80% of the cost incurred during implementation of GIS technology lies in data acquisition, data compilation and database development

Developable surfaces used in projected coordinate systems

cylindrical planar conic

attribute

data about an entity. stored in a database for vector GIS.

OSM problems

data are not compelte or consistent across the world accuracy of data unknown no systemic and comprehensive quality assurance processes no intention of univeral coverage or social equality

secondary geographic data capture

data collected for other purposes can be converted for use in GIS raster conversion scanning of maps, aerial photos, documents, etc important scanning parameters are spatial and spectral (bit depth) resolution

SUMMARY of week 7 lecture

data collection is very expensive, time consuming, tedious and error prone good procedures required for large scale collection projects, main techniques: primary, raster-remote sensing, vector-field survey. secondary: raster-scanning, vector-table digitizing

managing GIS error

data lineage statement records the data development history from source to current format, gis analysts must track and document error in metadata

describe the main phases of data stream?

data source: analogue or digital, these must be encoded whether by digitizing, scanning, data transfer, or keycoding, this constitutes data capture, and then you must edit/clean the data which is knowing that there are errors/uncertainty in the data, and must filter through those. errors can occur from the data source problems like resolution, and clarity, or occur through conversion, transfer process where like fingerprints, smudges were digitized and makes the spatial data messed up, there are also attribute data problems could be misspellings, mislabelings, things missing, duplicate labeling, labels missing things like that that should be corrected, more difficult to detect spatial data issues, then reproject onto a uniform projection so points are aligned correctly, generalize , this has to be done because different map sheets and data sources will have different resolutions and scales, so you may have to generalize a larger-scale map to match the resolution/scale of a smaller-scale map, edge match/rubber sheet to compensate for mismatches in the data at the edges, creating topology in the vector layers, delete redundant map sheet boundary lines, rubber sheeting (conflation) stretching the map in various directions because of internal distortions. objects on the map that are accurate are tacked down while othersthat were wrong location or have the wrong shape are stretched to fit with the control points. the control points are fixed features that may be easily identified on the ground and on the image. layer all of the map sheets, and then you have an integrated GIS database

Functions of traditional map

data store, carrier & info presenter

what is the data stream?

data stream is the model for creating an integrated GIS

how is an integrated GIS created?

data stream model: from data source digitize them, data capture, edit/clean, reproject, transform, generalize, rubber sheet/edge match, layer them, BOOM

DBMS

database management system, defined as a computer program to control the storage, retrieval and modification of data load data from files, databases and other applications index for rapid retrieval for manipulating attributes associated to features

critical cartography/counter-mapping

defined as 'a one two punch of new mapping practices and theoretical critique' new practices: non expert, distributed, artistic, open source, on the web collaborative theoretical critique: situations maps within specific relations of power and not s neutral scientific documents goal not go get rid of maps but to place production of maps in social context to better understand their message and limits expand access to production of maps so everyone can contribute related to critical GIS, but more focused on representation and mapping, less on spatial analysis methods

data quality

describes the overall fitness and suitability of data for a specific purpose data quality can be assessed by understanding: uncertainty accuracy precision bias error

deterministic or stochastic

deterministic methods of interpolation can be used when there's sufficient knowledge about the geographical surface being modeled to allow its character to be described as a mathetmatical function. this is rare. to handle uncertainty stochastic (random) models are used to incorporate random variation in the interpolated surface

what problems are faced when encoding digital and analogue data?

different formats, projections, resolutions, scales, etc, error/uncertainty

colorblindness

difficulty distinguishing between red and green

Manhattan distance

distance along raster cell sides from one point to the other. cannot pass diagonally through the block

gradual or abrupt

distinguished by continuity of surface produced. gradual methods produce smooth surface between sample points whereas abrupt methods produce surfaces with a stepped appearance. terrain models may require both methods

digital divide

distribution of resources is spatially uneven between dif social groups by race, age, location, education , these groups 'suffer from a lag' not just a problem of providing a tech, but of ongoing disparities in access to teh

external critique

do the author's claims make sense given all that you know? are there parts of the issue they ignore of data you are aware of that disproves their argument?

internal critique

do the author's claims make sense with the bounds of their argument? are they logically consistent?

unclassified

each data value has a different shade minimizes the amount of simplification and highlights subtle and complex patterns can be difficult to tell the difference between two similar shades

exact or approximate

eact methods of point interpolation honor all observed data points for which data are available. must not smooth or alter their values. appropriate when there's a high degree of certainty tattached to the measureents made at the observed data points approximate methods of interpolation do not have to honr the observed data points, but can smooth or alter them to fit a general trend. more appropriate when there's degree of uncertainty surrounding the measurements made at observed points

critical GIS history

early 90s: assumption of incompatibility of GIS with critical human geography methods, theory, and practice late 90's more engagement research agenda emerged: public participation GIS, feminist GIS, privacy, access and ethics, social history of GIS technology

overlays: raster approaches

easy to implement (assume all layers are matched-grid size, orientation), map algebra, boolean operations through map algebra a.) point-in-polygon b.)line-in-polygon c.) polygon-on-polygon problems with raster overlay: resolution and scales of measurement resolution determined by the size of the cell used. SPOT satellite data, collected at a resolution of 10m. have to change resolution if overlaid with resolution of 40m must be logical relationship between numbers, cannot come from difference scales of measurement (nominal, ordinal, ratio, interval)

codes of ethics

establishing code of ethics for internalist ethics is much easier than for externalist ethics internalist ethics are often more agreed upon externalist ethics are by their nature ideological and political, so harder to find common ground

social accounting concepts

establishing trust between users(ebay ratings)

spatial variation in data

even with geomasking, if there are only a few cases in an area it won't protect data eg randomizing point location by 500 m in a rural area with all houses more than 1km apart could increase level of randomization or remove outliers to address this issue

uncertainty

factors which affect data quality and our ability to trust the data accurately represents reality accuracy: extent to which an estimated data value approaches its true value precision: the recorded level of detail of your data

ingredients of network analysis:

features: nodes/junctions, edges attributes: connectivity (how many intersections), geocoding (address matching), transit cost/impedance analysis: shortest path, traveling salesperson, location-allocation modeling, how to distribute resources across the network based on supply/demand

vector: point-in-polygon

find out the polygon in which a point is located

what methods are available for detecting and rectifying errors in attribute and spatial data?

for attribute data: impossible values (not within range), extreme values (outliers) , internal consistency (checks against summary stats provided with source documents, find discrepancies), scattergrams (if relationship between 2 variables, can find outliers), trend surfaces (values that don't go along with the trend) spatial data is harder to detect but compare with the original data sources (digital or analogue spatial data sources) , looking for dead end nodes indicates missing lines, look for these features to direct editing rather than having to examine the whole map. visual comparison good starting poin. missing entities and noise are problems too with raster data. unclosed polygons, missing lines or points, duplicate label points, unlabelled polygon

attribute data

frequently stored separately from spatial data, feature identifier associated to attribute table: point attribute table, line or arc attribute table, polygon attribute table

overlay problems

generation of sliver (or 'weird') polygons. these appear after the overlay of two data sets that contain the same spatial entities. if digitized by 2 dif people 2 separate representations of the area would be created. if these were overlaid, long thin polygons would be seen along the boundary instead of a single line. sliver polygons arise from inconsistencies and inaccuracies in the digitized data. difficult to comprehend when more than 4 or 5 factors are involved most overlay procedures in GIS do not allow for the fact that variables may not be equally important when mapping variables for overlay analysis decisions about threshold values are important and depends on the choice of threshold values

neography issues

geographic information providers/consumers the general info provision model is changing from a centrally collected and brought togehter mode into a networked participatory model increased prevalence of user generated content is blurring the difference between producers and consumers what info do we trust? an emerging role for the traditional data provider is to perform data verification, to facilitate ease of use and access, and to ensure a good user experience how do we determine quality of data? authority and assertion, quality vs reputation, who is the contributor? digital divide: access to technology, only 62% of canadians in the lowest income quartile have internet access education and training privacy: data rights, computing everywhere

overlays: vector approaches

geometrically complex, requires topology and geometry (topologically correct) to be reconstructed, spatial boolean operations a.) point-in-polygon b.) line-in-polygon c.) polygon-on-polygon

Conclusion: mapping possibilties

geovisualization expanded the emphasis on the delivery of information to also encompass its exploration: so 1. mapping no longer in the hands of experts (map hacking, map mashups), 2. the scientific method of hypothesis testing and pattern confirmation no longer adequate instead maps and GIs used for "abduction" or exploratory methods of data mining and pattern-seeking exploratory methods are now well known in mapping, GIs and collab work Robinson's estab of modern (post war) cartography on apolitical empirical and scientific grounds, segregated from context, has been a target of critique from its beginning. contemporary critical cartography is situated in this long critical tradition critical cartography 'refers to the choice of new worlds, new societies. Here, the practice of hte cartographer is immediately political' critical approach is both an ethos and a practice, Kantian process of questioning. 2 areas of traditional disciplinary modes of cartography have come under question, theoretical enquiry which seeks to examine the social relevance of mapping, its ethics and power relations, and on the other hand, the development of open source and pervasive mapping capabilities. maps as resistance, counter mappings and participatory GIS map hacking provides a whole series of inexpensive or open source capabilities that combine spatialized knowledges in ever new ways. not the tech thats important, but how it's used and with what effects

spatial interpolation

given a limited set of known data construct a surface (sample points, transect lines, selected areal sampling) most common applications: elevations collected across the landscape, construct a DEM generate surfaces of pollution, oil deposits, mineral deposits, income, etc used to estimate a value of a variable at an unsampled location from measurements made at other sites, spatial interpolation is based on the notion that points which are close together in space tend to have similar attributes wide variety of choices, each of which can produce a very different surface spatial moving average (inverse distance weighting) is the most commonly applied method most important consideration: know the characteristics of the often unknown surface you are trying to create, and select the method that best enables you to reconstruct that surface common application: contour lines degree of uncertainty

local or global

global interpolation methods apply a single mathematical function to all observed data points and generally produce smooth surfaces. local methods apply a single mathematical function repeatedly to small subsets of the total set of observed data points and then link these regional surfaces to createa composite surface of whole area

location privacy

google maps, wifi locators, ip address locators all reveal locations protection: regulatory strategies: normally government rules on the use of personal info privacy policies: trust based agreements between individuals and whomever is receiving their location data anonymity: use a pseudonym and create ambiguity by grouping with other people obfuscation: reduce the quality of the location data

GMS

graphical manipulation software: spatial data, for manipulating features (adding, editing, deleting)

scanning limitations

hard copy maps are often unable to be removed to be scanned hard copy data may not be in a form that is viable for effective scanning, eg maps are of poor quality, or poor condition geographic features may be too few on a single map to make it practical, cost-justifiable to scan often on busy maps a scanner may be unable to distinguish the features to be captured from the surrounding graphic information it is difficult to read unique labels for a geographic feature effectively scanning is much more expensive than manual digitizing, considering al the cost/performance issues

DBMS Cardinality

how data tables within a database link together One-to-one eg between a country and its capital One-to-many: between state and its cities Many-to-many: between people and cities they've lived in

reflexive

how does your own position and identity influence the analysis? what are you unsure of?

selecting threshold criteria

how to define threshold criteria used for constraints. choice of population density chosen by who? based on what?

choosing classification

if constant numbers=equal interval or quantiles if normally distributed=standard deviation if has clear breaks=natural breaks

critique of pure reason

immanuel kant (1781) involves laying out and describing precisely the claims being made, and then evaluating such claims in terms of their original meanings

integrating data-overlays

important operation: ability to combine layers of info overlay analysis Ian McHarg-sieve mapping

pythagorean geometry

in a raster GIS more than 1 way to answer what the distance is between 2 points normally the shortest path, or Euclidean distance, is calculated by drawing a straightl ine between the end points of a line, creating a right-angled triangle so that Pythagorean geometry can be used

vector neighborhood operations

in spatial statistics toolbox: analyzing patterns, cluster detection, measuring spatial distributions with vector, neighborhood is defined using topology

spatial data editing and manipulation

incompleteness of data (missing points, lines, polygons), locational placement errors of spatial data: careless digitizing or poor quality from original data source, distortion of the spatial data: caused by base maps that aren't scale-correct ove rthe whole image incorrect linkages between spatial and attribute data: incorrect uinque identifiers (labels) being assigned during manual key digitizing. topology verification project/transform edgematching rubber sheeting/ geo-referencing

critical GIS methods

incorporating qualitatives naalysis (survey, interview, ethnographis data) public participation GIS (PPGIS): collaboration and inclusion in gIS indigenous GIS: incorporating other cosmologies, worldviews, epistemologies, and ontologies into a GIS

ecological fallacy overlay problem

inferred that data for areas under study can be applied to the individuals within those areas. will change appearance of data when overlaying

internalist and externalist ethics

internalist: mapping/analysis should be as accurate as possible, data should be complete and presented fairly, costs and benefits should be weighted, empiricist, being as honest about uncertainty and error, data security and privacy, cartographic representation externalist: placing GIS in its wider social context. GIS practices should be placed in an ideological framework how does use of GIs affect our social world? what work does it do? political

Overlay analysis: vector

intersect tool: retains common features, when you want to find areas that meet BOTH of two criteria, Identity tool: retain input features plus intersections, what portion of a floodplain includes agricultural parcels, union tool: combine all features into new layer, merge features from two layers

Kant on critique

involves laying out a describing precisely the claims being made, and then evaluating such claims in terms of their original meanings, people constantly and restlessly strive to know and to challenge authority seek to release the emancipatory potential of a society repressed by technology, positivism and ideology capitalism, instead of dying as Marx predicted, became more deeply established by co-opting the cultural realm. mass media pumping out low qual films, books and music, substitued for people's real needs. instead of seeking freedom and creativity, people were satisfied with mere emotional catharsis Michael Foucault, extending Kant's ideology, says that critique isn't amassing a body of knowledge but an attitude, and critique of what we are is at the one and same time the historical analysis of the limits that are imposed on us and experiment with the possibility of going beyond them power did not emanate from top of class hierarchy, but diffused horizontally in a fragmented way. what is critique? it is politics of knowledge 1. it examines the grounds of our decision making knowledges, and it examines the relationship between power and knowledge from a historical perspective, and 3rd it resists, challenges and sometimes overthrow our categories of thought not some deliberate political project, if the way that we make decisions (based on knowledge) is changed, then a political intervention has been made. critique can therefore be both explicit and implicit. not to say our knowledge is not true, but that the truth of knowledge is established under conditions that have a lot do with power.

Ecological fallacy in the context of GIS and solutions

is an error in the interpretation of statistical data in an ecological study, whereby inferences about the nature of specific individuals are based solely upon aggregate statistics collected for the group to which those individuals belong. This fallacy assumes that individual members of a group have the average characteristics of the group at large. Solutions: Sensitivity analysis that examines the magnitude of change caused by variation in scale and zoning configurations Avoidance - create spatial units in way to optimise homogeneous attributes (i.e. minimise spatial variation in data) Dasymetric mapping - uses auxiliary (correlated) data to statistically relate disaggregate data Sensitivity analysis that examines the magnitude of change caused by variation in scale and zoning configurations Disaggregating aggregations

Aspect

is the compass direction that the sloping surface faces at each location (0-360)

Resolution

is the size of the geographic units.

Extent

is the size of the study area.

how do source data type and nature affect data encoding?

it affects data encoding because different data sources have varying formats, resolutions, scales, and projections. analogue spatial data takes more time and is very expensive to digitize through manual, automatic digitizing, scanning or keycoding and can cause numerous errors/uncertainties in the digital form. digital spatial data can be downloaded or transferred to the database, less expensive

why is data editing important?

its important because there are often errors/uncertainty in the digitized data from either the data source (especially if digitized from an analogue source, could be smudges, differing resolutions/scales), through the conversion process, data transfer process, and digitizing. must check for missing points, duplicate points, overlapping points, as well as attribute data accuracy. basically you have to filter out as much error and inaccuracies as possible to move forward

managing data capture projects

key principles: clear plan, adequate resources, appropriate funding, and sufficient time fundamental tradeoff between, quality speed and price

the personal is political

linking GIS analysis to personal oral histories and narratives

case study: beyond ground truth

literature on GIS and local knowledge often assumes a binary of local indigenous nonexpert culture versus state/government, scientific, expert science paper shows how both local and expert knowledge are cultural social and political study area: pali district in India herders se forest as important art of livelihood and grazing, professional foresters from government want to manage forest to prevent overgrazing therefore conflict over ecological future of forest and access to it herders argue grazing land area decreasing, need more grazing access. professional foresters argue overgrazing occurring need to expand forest area traditional GIS would seek to measure 'actual' land use changes occurring. Robbins method instead constructs 2 different land use layers based on the different understandings of herders and foresters example of critical GIS approach: do not take categories as given, seek to use GIS methods to better understand political conflict and disagreement ground truthing: went to 143 locations and checked accuracy of layer from satellite images then asked the 2 groups to identify land cover from selection of photos: then classified entire image based on their local classifications to come up with herder-defined land cover and a forester-defined land cover map so ended up with 3 layers: land cover ecology from the satellite image, herder-defined land cover categories, forester-defined land cover categories disagreement on basic land cover categories Conclusion: GIS can be used to compare differing interpretations of the landscape, but only shows the product of these different cultural and social frames the normative resource priorities of all these groups must be placed front and center for debate, along with and the very political conflicts from which they aris. cannot substittude GIS Analysis for politics

spatial interpolation types

local or global exact or approximate gradual or abrupt deterministic or stochastic

MCE issues

main problems are choice of MCE algorithm and the specification of weights different MCE algorithms may produce different results when used with the same data and same weights, differences in the way trade offs are performed

What are the qualities of significant decisions requiring analysis:

many factors to consider not just one objective, i.e. triple bottom line for environment, social and economics big stakes long term implications many affected groups uncertainty in decision criteria

open source mapping

map hacking, the practice of exploiting open-source mapping applications or by combining one site's functionality with another's (map mashups), exploitations are possible bc of etensible markup language (XML) and APIs a people's cartography

1. links geographic knowledge with political and social power

maps and GIs are site of knowledge production, form of social power

theoretical critiques

maps make reality as much as they represent it the cartographic gaze code subjects and produce identities mapping as a production of space, geography, place and territory as well as political identities people have who inhabit and make up these spaces, maps are active and exercise power mapping isn't binary art/science/ objective/subjective scientific/ideological mapping often partisan, for state interests

Jeremy Crampton, John Krygier what does the reading mean of a 'one-two punch'?

means: pervasive set of imaginative mapping practices and a critique highlighting the politics of mapping-an undisciplined cartography two trends resist and challenge the historical methods and practices of mapping bottom-up without top-down control. no academic discipline so undisciplined cartography, freed from the confines of the academic and opened up to the people

Euclidean buffers

measure distance in a two-dimensional Cartesian plane, where straight-line or Euclidean distances are calculated between two points on a flat surface (the Cartesian plane). Euclidean buffers are the more common type of buffer and work well when analyzing distances around features in a projected coordinate system, which are concentrated in a relatively small area.

vector GIS distance

measured using Pythagora's theorem to obtain the Euclidean distance. geoemetry also used to calculate perimeters and areas.

viewshed analysis

military, cell phone towers, fire towers, visual impacts of logging, new roads, wind turbines visibility analysis: identification of areas of terrain that can be seen from a particular point on a terrain surface

natural breaks

minimizes differences within groups, maximizes differences across groups classes are statistically different from each other reflects the underlying data distribution

Georeferencing

models of where things are (geographic coordinate systems and projected coordinate systems)

MAUP overlay problem

modifiable areal unit problem. scale problem. gerrymandering, everybody arbitrarily chooses boundaries. when arbitrarily defined boundaries are used for the measurement and reporting of spatial phenomena. overlaying will change the boundaries

vector: line-in-polygon

more complex output map contains 'roads' split into smaller segments representing 'roads in forest areas' and 'roads outside forest areas' topological information must be retained in the output map. output map will contain a database record for each new road segment

critical theory

must be 'explanatory, practical, and normative' must explain what is wrong with current social reality, identify the actors to change it and provide both clear norms for criticism and achievable practical goals for social transofmration the philosophers have only interpreted the world in various ways; the point is to change it crtiiqe of epistemology and ontology underlying GIS: how does GIS affect our understanding of knowledge and existence/categorization? borrowing insights from feminism:

emergence of neogeography

neogeography mashups differentiated by their methods of data collection: whether they integrate data or services from multiple existing databasees, or whether they obtain and supply data back to the community through crowd-sourcing tags form an important characteristic in Web 2.0 and allow users to create their own semantic categorization (folsonomies) decentralize the formal classification of objects by using a virtual classification schema based on meta information defined by users mashups: combining information from several websites and sources to produce a new web service became known as a mash up

Queries: non spatial and spatial

non-spatial (table query): use SQL to query the attribute data use the interactive nature of the GIS to select a feature using the mouse and to examine the feature's attributes spatial: 'select by location'-implies that a spatial analytical question is asked method of retrieving data, important and useful at all stages of GIS analysis for checking the quality of Raster GIS measurements and vector measurements

probabilistic or statistical model

not deterministic, but we can model the aggregate effects using probabilities or statistics like spread of influenza-exact path of spread of disease is unknown but we can predict what percent of population will contract the disease, and the general outcome can be predicted when we have a priori knowledge and can assum causality statistical models: based on observations we can calculate correlations between attributes and therefore make predictions of future states, but that doesn't imply causality

problems with spatial process models

not enough historical data for analogue model to predict anything, hard to extend a predication based off a small sample to a wider area, original data didn't consider use for GIS, may ignore or not include geographical information

shortest path problem

not only based on shortest distance, but travel impediments like traffic, congestion, slope all taken into consideration

conceptual models-system models

one of the initial stages in the development of a GIS application usually expressed in verbal or graphical form, and attempt to describe in words or pics quantitative and qualitative interactions between real-world features. systems diagram, using symbols

Database relationships

one to one, one to many, many to many

deterministic model

only one possible answer for given set of inputs based on concept that the behaviour of geographical systems is controlled by natural, physical laws. once these laws have been unearthed, the system's behaviour can be predicted common in physical geography, where laws of physics apply less easily applied in human geography however at aggregate level we can model trasnportation systems, communication systems works well with clear, structured data very rare

Relation rules

only one value in each cell (intersection of row and column) all values in a column are about the same subject each row is unique no significance in column sequence no significance in row sequence

OSM

open street map is a knowledge colelctive that is creating a meaningful geographic data includes a peer production network as different groups within the organization are focusing on the deelopment of different aspects of hte project utilizing community computing grids in the process of rendering the various map tiles using a common program uses social mobile computing during the process of data collection

Web 2.0 mapping examples

openstreetmap crowd sourcing is how large groups of users can perform functions which are either difficult to automate or expensive to implement content is created for free, for the devlopment of the community create a set of map data that are free to use, editable, and licensed under new copyright schemes update cycle is faster nad may take into account arpid changes over 18000 members

database approach

organized data, enhanced access (multiple users, levels of security) redundancy minimized (one dataset sorted/searched multiple ways) multiple data access methods easier to maintain and update (standards) independence of data from application access can be controlled and centralized security: user roles and permissions standard query languages (Structured Query Language-SQL)

John Snow 1854

outbreak of cholera maps

Equal Interval

places boundaries between classes at regular intervals, pros: easy to interpret, classes appear logical cons: does not account for data distribution, can result in empty classes or classes with many values

quantiles

places the same number of observations in each class pros: no classes with too few or too many values cons: can separate very similar values, or group very different values

Stages in Data Collection projects

planning-->preparation database design-->obtain data digitizing/transfer-->editing/improvement-->evaluation/verification-->planning what is the source? how reliable is the data? how often does it change? ongoing cycle-technology change Data collection is one of the most expensive GIS activities. two broad types of collection, data capture (direct collection), primary (direct measurement), secondary (indirect derivation), data transfer

Network DBMS Model

precursor of relational hardwired/manual coding in rograms failed as IBM stuck to Hierarchical and relational more powerful points, lines, and polygons can share relationships

what is geocoding?

process of converting address to point form

geocoding

process of converting an address int oa point location non geographic descriptor (like address, place name, property) is used to determine the geographical coordinates of a location

what is data encoding?

process of digitizing or transferring data from sources onto the computer for creation of maps

address matching

process of geocoding street addresses to a street network. locations are determined based on address ranges stored for each street segment

PPGIS

public participation GIS developing out of participatory approaches to planning and spatial information and communication management. practice is the result of a spontaneous merger o Participatory Learning and Action methods with GI techologies geared towards community empowerment through measured, demand driven, user friendly and integrated application of geo spatial technologies there were criticisms to GIS: only for elite people with money and access, and for lack of knowledge based input via the Internet, more accessible to people.

Arthur Robinson

quality of maps available and problems in training cartographers in 1950s were driving force behind Anglo-American cartography Robinson factored in the user in the equation of map design worked at Office of Strategic Services from 1941-46, worked to provide unbiased and reliable maps of military theatres and landing zones-in a time of Nazi maps segregated and apolitical cartography developed throughout 70s

Using GIS decision analysis terminology, a spatial MCA system can do which one of the following combine criteria, objectives, and alternatives scores to identify weights rank alternatives by calculating the sum of the weight times the score for each location Create standardisation functions for each alternative Score each objective by the criteria

rank alternatives by calculating the sum of the weight times the score for each location

weight

rank the layers according to their importance from 0-1

process of constructing a GIS data model

real world-->spatial data eg map-->spatial data model (raster and vector) --> spatial data structures-->computer

Relational Database: Topological data model

relational: relations between tables defined by primary keys (eg node #, line #) planar enforcement: no two individual features can overlap there are no 'holes' or 'islands' that are not themselves features every feature is represented as a record in the attribute table topology: objects store information about their relationship with their neighbors (adjacency, connectivity, intersection)

Run Length Encoding

replacing a long series of a repeated character with a count of the repetition i.e Full Matrix-100bytes 0000000000 0001111100 Run Length (row)-44bytes 0,10 0,3,1,8,0,10

Thematic Maps

represent and illustrate the spatial structure, patterns and interrelationships for a single theme, rather than just the location of geographical phenomena

analytical or process model

representations of phenomena in the real world to aid in decision making process, natural processes that occur taken into consideration (effect of climate change, acid rain, habitat change)

what are reprojection, transformation, and generalization?

reprojection is projecting a uniform map projection and origin point (datum) onto all of the map sheets and layers in order to reduce distortion and keep them all aligned transformation: data derived may come from different coordinate systems. grid systems used may have different origins, different units of measurement or different orientation so you have to trasnform the coordinates of each of the input data sets onto a common grid system, done through linear mathematical transformations

what methods are data editing and conversion are used in GIS?

reprojection, transformation of coordinate systems, rubber sheeting, edge matching, filtering out errors from data source/conversion

source data resolution

resolution describes the smallest feature in a data set that can be displayed or mapped raster resolution: grain: refers to the finest spatial resolution within a given data set

ethics

responsibility, professionalism, social context

identity

retain input features plus intersections

traveling salesperson problem

salesperson needs to visit a specific set of clients in a day, and to do so by the best route (usually the quickest) which order should the stops be visited?, least cumulative impedance

technologies of cooperation

self organizing mesh networks: peer-to-peer networks, different nodes in the network are using hte resources of other nodes in order to accomplish a task. community computing grids: people share computing resources by voluntarily running applications on their computers and exploiting unused computing capacity peer production networks: enabling people to work together on a specific task, often without monetary renumeration

optimum paths

shipping companies and airlines-minimize travel time and fuel costs in relation to currents and winds, utilities companies-locating the optimum route for power lines, pipelines, optical cables underwater highway construction the least cost path across a landscape

externalist ethics:

software intellectual property rights, free (no licensing fee) and open source (source code open to public who have the right to read, change and distribute it) vs proprietary software (not free: licensing fee, source not open, hidden from public, copyrighted, cannot be read or altered) geo-surveillance: red lining (blocking off entire areas in GIS technology), neghborhood rating apps (questionable ethics, ghetto locator, crime reporting, can reproduce racist fears and affect people's decision making in questionable ways), surveilling where criminals go, etc cartographic rationality: constituion of populations needing management or control through mapping their locations

network analysis

solving problems on a street network, vehicle routing, nearest point, directions, service areas network: a series of points and lines that are connected together network is a set of interconnected lines making up a set of features through which resources can flow

sources of data error

source data sets, human error, incorrect choice of gis methods, computational errors, incorrect interpretation of GIs results

standard deviation

statistic that indicates the amount of spread around the mean classes are centered around the mean value good for showing above and below average values

SQL

structured query language Example is select by attributes tool SEQUEL: Structured English Query Language shortened Developed by IBM in 1970s Now de facto standard for accessing relational databases example: SELECT*FROM books WHERE price>100.00 and price < 150.00 ORDER BY title

vector primary data capture

surveying: locations of objects determined by angle and distance measurements from known locations, uses expesnie field equipment and crews, most accurate method for large scale, small areas GPS: satellites used to fix locations on Earth's surface, differential GPS used to improve accuracy can become as accurate as 10 cm

digital spatial data

tabular data: digital file transfer, like census data map data: digital file transfer with reformatting aerial photographs and satellite imagery all require file transfers

When you create a GIS decision analysis system, stakeholders can be involved in developing the system. How are stakeholders involved in the process?

takeholders preferences are captured as weights for the criteria

reclassification

taking interval/ratio measurements (temp, precip) and putting them into classes (hot/cold, wet/dry) taking soil types and putting them into classes (good/poor) reducing the complexity in order to highlight patterns, select important attributes from each layer before overlaying, reduce the overall complexity of the final result by reclassifying into fewer classes, discard unimportant information reclassifcation is a simplification process that involves loss of data! creates boolean image

social mobile computing

technologies allowing coherent activities among a group of people , some of whom are complete strangers

Web 2.0

technologies of change the early web was primarily one directional, allowing a large number of users to view the contents of a comparatively small number of sites Web 2.0 is a bi directional collaboration in which users are able to interact with and provide informaiton to central sites, and to see that information collated and made available to others

group forming networks

technologies that alllw subgroups to be formed and interact

knowledge collectives

technologies that allow people to share information and set the structures and rules of managing common resources (like Wikis and blogs) important to note that moving away from isolated technology in to the embodiment of technology within social activities

mapping mashups

term refers to web maps that rely on easy, fast integration, frequently using open application programming interfaces (API) and data sources to produce enriched results that were not necessarily the original reason for producing the raw source data most basic and early form was visualizing data on top of a Google map, but now much more advances

OGC Protocols

the Open Geospatial Consortium, an international voluntary consensus standards organization, originated in 1994. in OGC, more than 400 commercial, governmental, nonprofit and research organizations worldwide collaborate in a consensis rocess encouraging development and implementation of open standards for geospatial content and services, GIS data processing and data sharing

Z value

the elevation assigned to an x/y coordinate 3rd dimension

edge matching

the joining process has 3 basic steps, to correct small differences and mismatches when the map sheets are layered 1. mismatches at the sheet boundaries, may be misaligned, and join the entities 2. for vector layer, topology must be created 3. redundant map sheet boundary lines are deleted or dissolved

edges

the lines connecting to the points

data error

the physical difference between the real world and the GIs representation 2main types of error: single error: unique or individual flaw in data persistent, widespread error: occurs throughout the whole data set

nodes/junctions

the points

Hierarchical DBMS Model

the relationship between every point and line is specified separately, always tree diagram, relationship 1 to M, easy/fast to answer 'establish queries' but hard for non-standard populalar early mainframe DBMS not used in DBs anymore, but still used in filing or computer storage

rubber sheeting

there may still be internal distortions from data sources in individual map layers, like from aerial photographs due to the movement of the camera. so you have to stretch the map in various directions as if drawn on a rubber sheet

digitizing limitations

think about topology vs spaghetti

scale analogue model

topographic maps and aerial photos are scale models: reproducing certain features in a scaled down form

TIN

triangulated irregular network elegant way of constructing a surface from a set of irregularly spaced data points. spatial interpolation method often used to generate digital terrain models. TIN model is an exact interpolation method based on local data points. adjacent data points are connected by lines to form a network of irregular traingles. distance between is calculated from known points

The number of business customers around a main road may be found by a query 'select by location' to identify customers within a distance. Can the same result be alternatively found using a spatial join operation in GIS.

true

neighborhood operations

used identify trends/patterns and outliers: compute local vs global statistics, simplification (smoothing), exaggeration (increase differences), hot/cold spots (identify local outliers) spatial analyst has neighborhood and zonal routines that work with regions of various sizes/ definitions values of individual cells are altered on the basis of adjacency are called neighborhood functions. filtering is one example used for the processing of remotely sensed imagery. filtering will change the value of a cell based on the attributes of neighboring cells. smooths noisy data.

social software

users build profiles that can be shared linking people from disparate geographical loations into virtual places networks of indiviauls are dichotomous between real and virtual acquaintances

analogue models-natural

uses actual events or real world objects as a basis for model construction to make predictions ex: avalanches, pattern of past avalanches to predic formation of new ones historical analogs: old lanscapes can predict hte future form of present landscapes spatial analogs: understaning a landscape in one locale helpts in understanding process and form in another place examples: tabular data so you gotta do keyboard entry, text scanning. address lists of hotel guests, tables of regional tourism stats from official publications map data: requires manual digitizing, automatic digitizing, scanning, historical maps, infrastructure and administrative maps aerial photographs: manual or automatic digitizing, scanning

slope

uses: geomorphology, road construction costs, hiking trails/ski runs, legislation-logging practices steepness or gradient of a unit of terrain, as percentage or angle in degrees

aspect

uses: snow pack/water runoff, vegetation growth, agricultural models direction in which a unit of terrain faces, usually in degrees from north

mathematical (process modeling)

using the language of mathematics to represent the actual physical/mental (conceptual) processes that occur in the past such models were necessarily developed outside of GIS, then GIS was used to create, manage the spatial data, and display the results increasingly, GIS software includes the ability to implement spatial process models uses deterministic, stochastic, and optimization methods.

data security

weighing individual confidentiality vs public access to information, protect privacy and security. sensitive disease data, residential addrress data methods to address: 'geomasking' or 'spatial skewing' applying random variation to point data aggregating up: group point data into census blocks, counties

visual complexity

when 2 complex maps are overlain the output is likely to be more complex. makes difficult to interpret.

optimization model

widely used in many different fields: minimization of travel distance minimization of construction costs optimum paths for powerlines, highways forestry: distances between the stands and the mill location of a chain store relative to population/other chain stores used to minimize or maximize some aspect of the model's output. helps identify the area of minimum or maximum effects

Which one of the following features CANNOT be derived from a DEM dataset? Viewshed z-scale TIN Aspect

z-scale

Differences between TINs and DEMs

• Both DEM and TIN can be used for terrain analysis • DEM can be converted into a TIN, and a TIN can also be converted to a DEM • TIN is flexible with input data sources • Can use DEM, contour lines, GPS data, LiDAR data etc. • Can add elevation points to a TIN at precise locations and add breaklines, such as streams, roads, ridgelines and shorelines to define the surface discontinuities • DEM is fixed with a given cell size • cannot add new sample data to increase its surface accuracy; • DEM is efficient for terrain analysis, such as generating slope, aspect, etc.

Classification and a description of the different types

• Defined interval - Gross total divided by number of classes. 100 total scores, class 1 1-10, class 2 10-20 • Quantile - Number of data points divided into equal classes, 10 number 2 classes, 5 numbers per class • Jenks natural breaks - find natural breaks in data • Geometric interval • Standard deviation

Examples of Bias in Maps

• Maps are not neutral • drawn according to dominant philosophies and paradigms of the time • reflect the dominant power of the time • Map projection • Data accuracy issues • Human errors

Types of Projection and uses

•Conformal -scale is preserved and attempts to preserve shapes of features Cylinder projection (useful for navigation). •Equal area ‐ attempts to preserve areas of features (useful for calculating areas). •Equidistant -attempts to preserve distances (useful for calculating distances). •True direction (azimuthal) -attempts to preserve directions with respect to the centre (useful for navigation).

Advantages of Raster Analysis

▫ Ability to analyse continuous surface variable, i.e. slopes, density, etc. ▫ Surprising flexibility and simplicity to perform other spatial analysis on proximity, hydrological models, identifying local trends i.e. hot spots, travel time to destination, etc.

Explain, using examples, what the differences amongst local, neighbourhood, zonal and global operations in raster data analysis are.

▫ Local - operating on each cell value in layer(s) (e.g. To get an idea of the distribution of habitat across the State you want to map high, low and medium quality habitat.) ▫ Neighborhood - on each cell as focal cell and its surrounding cells (e.g. You think that the determinant of whether tigers are likely to occur at a location will not only depend on the habitat quality at the location, but also on the quality surrounding a location. You therefore want to map this.) ▫ Zonal - on groups of cells identified by zone (Finally, to prioritise your search, you want to map the average habitat quality for each suburb across Tasmania.) ▫ Global - incremental operations on entire raster, i.e. distances between locations of interest Local: per-cell Neighborhood: local cell neighbourhood Zonal: groups of cells Global: entire raster