Intro GIS Exam 1 Review

Property Preservation-

-Distance-equidistant -Direction-azimuthal -Shape-conformal -Size- equal area *NO PROJECTION CAN PRESERVE BOTH SHAPE AND SIZE, & NO PROJECTION CAN PRESERVE THEM ALL AT THE SAME TIME.

. What are the 6 pedagogical elements of GIS (science)?

-GEO-SPATIAL DATA -DATA ANALYSIS - DATA DISPLAY - DATA ACQUISITION - DATA EXPLORATION - DATA MANAGEMENT

LIght Source

-Gnomic(Center) -Orthographic(Infinity) -StereoGraphic- (other side opposite)

What are the five themes of geography and how do each of them play a role in the development and use of geographic information systems and geographic information science?

-Location, -Place, -Human-Environment interaction, -Regional, -Movement

Aspect-

-Normal- parrallel, earths axis parallel to developable surface. -Transverse-Earth's axis perpendicular to developable surface. -Oblique (orientation of developable surface)

Friction of Distance

-is based on the notion that distance usually requires some amount of effort, energy, time, and/or other resources to overcome. Because of this "friction", spatial interactions, especially transport and the particular case of human migration, will tend to take place more often over shorter distances; amount and intensity of interaction will decay with distance. Regardless of physical friction, the various costs are metaphorically assumed to correspond to forces that impede movements. Experience of distance according to time. Layers of friction can include terrain, weather conditions, accessibility etc.

6 pedagogical elements of a GIS

1 Geospatial data 2 Data analysis 3 Data display 4 Data acquisition 5 Data exploration 6 Data management

Develop-able Surface-

1.- Plane-(azmuthal) flat surface used for polar projections 2.-Cylinder-cylindrical-equitorial, ex. mercator projection, highest accuracy at equator 3.-Cone-highest accuracy at mid lattitudes ** No projection preserves global accuracy

what is the difference between geographic and projected coordinate systems, etc)?

A coordinate system is the reference framework used to define the positions of points in space A map projection converts 3D Earth surface to 2D flat surface A projected coordinate system takes datum and applies a map projection to it creating a highly accurate way to locate things in a local area

How are datums and ellipsoids related?

A datum is a surface of reference Use ellipsoids to model data

What is a GIS (system) capable of (in database terms)?

A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. ... In other words, data that is in some way referenced to locations on the earth. Coupled with this data is usually tabular data known as attribute data.

What are the key distinctions between absolute and relative location? How are they useful in different ways?

Absolute location- mathematical- coordinate based location, geographical cs (3D earth) Lat.-Lon.- UTM, cartesian/ planar cs (x,y,z) Relative location- descriptive Site: human and physical attributes at a location (building types, water features, soil characteristics, ect.) Situation- where a location is in proximity to other locations (1/2mi South off of 630)

How does map-making borrow from communication theory and visual psychology (cognition)?

Communication theory deals with how information is conveyed Visual psychology plays into how people perceive and process visual information Both of these should be taken into consideration when making a map to produce something that is clear, not misleading, and accurately represents the information

What is the continuous field data model?

Conceptual model for rasters, constant array/distribution of items, no blank spaces

What is the discrete object data model?

Conceptual model for vectors, individual entities in space

What are relevant examples of movement in geography? Pay particular attention to diffusion (3 types), time-space compression, the friction of distance, distance decay, etc

Contagious- Relatively even movement outward from a central point across space --spread of religions from Mecca Hierarchical- Travel from point to point--Plague diffusion in London, popular music Relocation- Migration When movement of a phenomena leaves little to nothing behind- loss of language

What are the key components of the raster data model?

Continuous Cells, pixels, array?

Types of Geospatial Data

Coordinate systems Discrete object continuous field

*3 T/F: chloropleth maps are best used to show raw totals (e.g. total population) as opposed to ratios (population density). WHY?

False better for population per square mile- population density.

*2 T/F: error in a map tends to be greaterin large scale maps as oposed to small scale maps. WHY?

False there is much less projection error on large scale maps. also, it shows a smaller area that is more zoomed in.

What are the three main categories of regions? Be able to provide examples of each.

Formal - common measurable characteristics throughout the enumeration unit. Spatial units from which data is gathered. Examples: political boundaries Watersheds Functional -any region delineated by a common node of activity - ex.:(flow analysis & watershed analysis) Perceptual- -cognitive bias & personal experiences - regions of the minds making -ex.: what defines these? mid-south Deep-south South-east South-west

How is generalization at the heart of the map-making process?

Generalization must be employed in order to make a map. In no map is there ever a 100% complete representation of the real world/model that is being portrayed. This relates to question 1 ^^^ in that generalization falls under all of these categories: improving interpretability, reducing clutter, boosting efficiency.

What was Waldo Tobler's key contribution to geography? In what ways is it relevant? Flawed?

Geographic Law All things are related and interdependent Nearer things are more related than things further apart Flawed because nearer things aren't always related, farther things may be super related through technology. NYC and London vs NYC and Albany

What are the primary components of a GIS (system/ structural)?

Hardware, Software, Procedures, People, and Networks

Geospatial Data

Information about a physical object that can be represented by numerical values in a geographic coordinate system.

Human-Environment interaction exists on a continuum that runs from determinism to coconstruction. Be able to articulate some of the types of theories about nature, society, and environment that exist along this continuum.

Nature v society Domestication of dogs Environmentalism determinism The environment determines how people behave Possibilism Environment plays a role, but humans have options Environment gives a range of possible outcomes Co-construction Human shapes environment, environment shapes the human

What are the key distinctions between space and place? Be able to provide examples.

Place is the personalized experienced space Ex: campus Space is your general location Ex: space between two cities

What are the key elements of the vector data model?

Points, Lines, Polygons (Discrete)

Be able to explain the role that property preservation (4 categories), developable surfaces (3 main types), aspect (3 types), trigonometry, and light source (3 types) play in the construction of projections.

Property Preservation- Distance, Direction, Shape, Area. Develop-able Surface- Surfaces- Plane, Cylinder, Cone. Aspect- Normal, Transverse, Oblique (orientation of developable surface) LIght Source/Trigonometry - Gnomic(Center), Orthographic(Infinity), StereoGraphic

Geospatial data (census, satellite)

Spatial data, also known as geospatial data, is information about a physical object that can be represented by numerical values in a geographic coordinate system.

Trigonometry- area of a triangle

Tangent (one line) Secant (two lines)

What is topology and what is its importance in GIS?

The study of properties and spatial relations that are unchanged by transformations such as stretching and folding. Ex. A border between countries should remain unchanged despite any distortion from projection.

Why do we need these two distinct models (what are their trade-offs, uses, benefits, detriments)?(vector & raster)

They are interdependent on each other. If you have a raster data model without a vector data model, your data will most likely not represent anything concrete or interpretable.

. Why do we need multiple datums, ellipsoids, coordinate systems, and projections?

To compensate for distortion, the irregular shape of the earth, and to maintain accuracy when mapping small or large areas and regions.

. How does Universal Transverse Mercator work (false easting, false northing, etc)?

UTM divides the earth into 120 (60 per hemisphere) "strips". Each is 6 degrees wide in longitude and extends 80 degrees south latitude and 84 degrees north latitude. This system loses accuracy at the poles.

*1data management

adding annotations and explanatory metadata and verifying sources for a feature dataset of municipal infrastructure in ArcCatalog

Geographic Information Systems?

aids in collection,coordination, output, analysis, maintenance, storage, distribution,for mapping spatial data and information. It has analysts and techs that look at the "what" and "where". Ex.- business stores its assets in a GIS system as points, lines, & polygons. The "where" is their physical geography on a map.Points may be towers as XY locations. Lines may be wires that are connected to each tower. Polygons may be the areas each line services. The "what" is information about their feature.

coordinate systems

certain points in space that make up a system for the purpose of determining location

Geospatial Data

data that describe both the locations and characteristics of spatial features on the Earth's surface

vector

data that represents features as points, lines, and polygons

Distance Decay

effect states that the interaction between two locales declines as the distance between them increases.

How is the organization of geographic data conceptualized and structured in the Georelational Data Model?

geographic data model that represents geographic features as an interrelated set of spatial and attribute data. The georelational model is the fundamental data model used in coverages.

Geospatial Data

items that are tied to specific real-world locations

raster

one of the two types of data, cells in a grid

*1data analysis

re-projection is more of a matter of display!!! -using interpolation to find missing variables in a location. A spatial statistical method to get missing data points. Geo processing *** reprojecting a set of shape filesfor wildlife preserves in Texas from a geographic coordinate system to a state plane (projected) coordinate system, WOULD BE INCORRECT!

datum

reference source

What are shapefiles? What are they comprised of (subfiles)? How do shapefiles compare with geodatabases (feature classes and feature datasets)?

simple, non-topological format for storing the geometric location and attribute information of geographic features Shapefiles contain the vector geometry .shx - Index .shp - geometry .dbf - database/attributes .prj - projection a geodatabase can be anything that allows you to store spatial data and perform spatial query on the data containing it. A shape file is a file based format for storing spatial data. So a shapefile is actually also a geodatabase. a shape file is a one-table-storage format. A table is also called a feature class in this context. So a shapefile generally contains just one feature type with a set of attributes or fields. A file geodatabase also contains feature classes, but it allows you to add more than one to it.

Geographic Information Science?

studies data structures and computational techniques. Is concerned with the "how". It conceptualizes how to store spatial information, collect data and analyze it. It encompasses all aspects of GIS such as remote sensing, surveying, mathematics, programming and geography.

time-space compression

the increasing sense of connectivity that seems to be bringing people closer together even though their distances are the same. Space time compression is the solution to distance decay because technology (internet,cell phones) is allowing us to communicate more across longer distances. Absolute distance doesn't change, but globalization brings us closer together.

How is the organization of geographic data conceptualized and structured in the object-oriented database structures?

the main feature of object-oriented databases is allowing the definition of objects, which are different from normal database objects. Objects, in an object-oriented database, reference the ability to develop a product, then define and name it. The object can then be referenced, or called later, as a unit without having to go into its complexities. uses a split data system (spatial data and attribute data in different files) and the two tables are linked by feature ID. Each map feature has a unique label ID. Attribute data are stored in a "Feature Attribute Table". Each map feature has a unique label ID.

How do choices about and differences in scale, representation strategy, style, and types and availability of data influence the appearance and interpretability of maps?

the more data that you have available to you, the better the representation in your map should be, and therefore an increased interpret-ability. The underlying factor is that efficiency is key. Having a non-cluttered, efficient, effective, and interpret-able map should be the goal.Choose colors that accurately represent what you're trying to convey (ex: using red for hot temps and blue for cold).

map projection

turning a 3d image into a 2d flat surface

*1Data Acquisition

using GPS to gather locational data for potholes along asher avenue.

*1Geospatial data

with respect to pedagogical elements of a GIS: deciding whether raster or vector representation best generalizes the real world phenomena being modeled.