Geography Quiz 3
Suppose you are asked to perform a query in the attribute table of Wisconsin roads. The table contains the following information of each road: "Road_ID", "County", "Width" and "Rank". For each road, "Rank" can take one of the 4 values: 1, 2, 3, 4. If you are only interested in the roads belong to Dane county with rank equal to or higher than 2, how would you construct the query?
"County" = "Dane" AND "Rank" >= 2
In the residential development example, why do we perform buffer operations over the roads and high school layers? What is the purpose of overlaying the two buffer layers?
Perform an overlay operation over the two buffer areas to find places within reasonable distance to both high schools and main roads. Perform a spatial query using two layers: the intersected layer from step 3 and the farms data layer. This selects farms located in the intersections of school and road buffer areas. So you can see it all on one map
Which is true?
Raster data model is especially suited for modeling geo-spatial phenomenon which varies continuously over geographic space
Which of the following is NOT used by GIS systems to display discrete features?
ANGLES polygons points lines
What types of features will exist in the result of an intersect operation over the two layers?
Agricultural land inside floodplain
What types of features will exist in the result of a union operation over the two layers?
Agricultural land inside floodplain, Agricultural land outside floodplain, and Non-agricultural land inside floodplain
What types of features will exist in the result of a symmetrical difference operation over the two layers?
Agricultural land outside floodplain, Non-agricultural land inside floodplain, and Non-agricultural land outside floodplain
Please select the questions which can be answered using GIS:
All are correct: How will the path of Superstorm Sandy affect voter turnout in the 2012 US presidential election? Where are the famous dishes at restaurants and bars in Belo Horizonte, one of the host cities for the 2014 World Cup? What are the factors leading to the habitat loss of elephant in Africa? How do technical, educational, and financial assistance to land managers in Wisconsin help reduce soil degradation?
Why is a title important to have on a map?
All maps should have a title which describes the content of the map. The title usually conveys the following information: What is the content of the map? Where is the geographic area? When did the geographic phenomenon or event occur?
Why are there a variety of definitions of GIS?
*Container of maps *Computerized tools for solving geographic problems *Spatial decision support system *Mechanized inventory of geographically distributed features and facilities *Methods for revealing patterns and processes in geographic information *Tool to automate time-consuming tasks.
What are "Geographic Problems"? How do we solve them using GIS? What are some examples?
DEF: Problems that involve location, either in the information used to solve them or in the solutions themselves How?: GIS is capable of recording, analyzing, and displaying information about LOCATIONS. A GIS is a system for analyzing and solving geographic problems EX: *Health care managers choose where to locate clinics and hospitals *Delivery companies design and update daily routes and schedules *Tourists navigate to a destination in an unfamiliar city *Forestry companies plan for sustainable tree harvest and replanting programs
A pharmaceutical factory needs to choose a suitable site for its manufacturing building. Considering the possible negative impacts on environment, the new building cannot be located within 100 meters to rivers. However for the convenience of employees it should not be very far from the town (say 5km) and should be close to the main roads (say 200 meters). How would you perform spatial analysis to find a suitable site? You Answered
1) build buffer zones around rivers, roads and the town, respectively; 2) intersect the three types of buffer zone to find the suitable site
What is buffer? Explain it using an example.
A buffer creates an area within a user-defined distance of an existing entity/feature. This feature could be a point, a line, or a polygon. Buffers have many uses, for example determining areas impacted by a proposed highway, and determining the service area of a proposed hospital. Buffer can be performed on both raster and vector data
Describe the differences between the attribute tables used in raster and vector datasets.
EX: the vector base table has each column as an attribute or property of a state, such as the sub region this state belongs to, the abbreviation of the state, and the population of the state. Each row represents a geographic feature - in this case, a state the attribute table has four types of land cover: forest land, wetland, crop land, and urban, each of which is displayed with a specific color in the map and a numerical value (1-4) in the attribute table. While the rows of the attribute table represents four land cover types (values 1 - 4), the columns show properties of these categories, such as type, count of pixel, and area
What is the role of GIS in geospatial technology?
GIS is used to store and manipulate the acquired geospatial data. Software systems with the capability for input, storage, manipulation/analysis, and output/display of geographic (spatial) information.
What is Moran's I? What is it used for?
Moran's I is one of the oldest indicators of spatial autocorrelation. It is a standard for determining spatial autocorrelation based on both feature locations and feature attributes. Given a set of spatial features and an associated attribute, Moran's I evaluates whether the pattern expressed is clustered, dispersed, or random.
What is the value range of Moran's I? What Moran's I values indicate positive/negative spatial autocorrelations?
Moran's I varies from +1.0 for perfect positive correlation to -1.0 for perfect negative correlation. If Moran's I equal to 0, it means a random pattern, indicating geographically random phenomena and chaotic landscapes
What is map reclassification? How do you perform it on vector or raster data?
Reclassification is reassigning values on an existing map based on the values of an attribute, e.g. land cover group. The reclassification of raster data is very straightforward. In Figure 4, the Base Raster (the original raster map) has pixel values ranging from 1 to 20. After reclassification by mapping the old values to new values via the table in the middle, the new image (output raster) only contains values from 1 to 5. Here is an example for vector data (Figure 5). Polygons which presents the house parcels are merged into big polygons. The map after reclassification is much generalized and simpler, carrying fewer details.
What are the differences between a scale-down inset and a scale-up inset? How would you determine which one to use in a specific mapping project?
Some maps have insets — smaller maps on the same sheet of paper. Inset maps can be used to show more detail or to show a larger region that isn't shown on the main map. For spatial informations that cannot fit in the same spatial context, we need an inset to either scale down or scale up. Scale up inset (smaller more detail) Scale down inset (bigger less quality)
What is the typical process to solve a GIS problem?
a. State the problem b. Collect and edit data c. Analyze the problem by performing spatial analysis on the data d. Produce maps for decision and policy makers that show the results of your analysis
What is attribute data? How is it associated with spatial data?
descriptive information about geographic features. Attribute data is important in GIS to link a geographic location (spatial data) or feature to its properties (county population, land cover type, and air temperature)
What is the raster data model? How does it represent geospatial data?
geographic features are divided and represented by evenly spaced grid cells (or pixels), typically use to represent continuous data (elevation, air temperature, population)
What are the six components of a GIS? Briefly describe their roles in GIS.
hardware: configuration consists of a desktop or workstation used to perform the most basic functions of GIS software: allows GIS to perform location-based analysis data: a digital representation of selected aspects of specific area son the Earth's surface or near-surface, built to serve problem solving or scientific research (most expensive) procedures: organization, budgets, training, customer mapping requests, quality assurance, and quality control people: design, program, maintain, and use GIS network: what makes GIS possible, it is the sharing of data, dissemination of maps, graphics, and information (network is in the center of the image because it connects all of them)
In which type of overlay does the new layer show only the common features of the other layers?
intersect
Which of the following is NOT a type of data classification commonly used by GIS in creating maps?
median
The means of data classification that creates a relatively even distribution of ranges (similar numbers of features in each class) on a map is the:
quantile method
The model used to represent continuous fields in GIS is the _________, which represents data in a set of ________.
raster data model; grid cells
You are visiting Seattle and receive a map from the Seattle Visitors Bureau showing the streets of downtown Seattle and points of interest. You are looking at a:
reference map
What is the vector data model? How does it represent geospatial data?
represent the geographic features with Points, Lines, and Polygons, typically used to represent discrete data (locations of restaurants, streets)
The information handled by GIS is primarily?
spatial
Which type of overlay eliminates the areas that the layers have in common?
symmetrical differences
What are the mean center and median center of a set of spatial features? How are they calculated?
the mean center is the "average" position of the points. To get this position mathematically, we need to calculate the average x and y coordinates of all sites.(the average x coordinate is the sum of all x coordinates divided by the total number of points) The median of a list of numbers is the middle one if these numbers are sorted from lowest to highest. To get the median center, we will sort get the medians of the x and y coordinates separately.
What is data query?
the most fundamental function in GIS and geospatial databases. For example, you can use it to search for nearby restaurants using Google Maps. In a more technical way queries can manipulate a geospatial database and select only the records you want
What is a map? What makes it a unique tool for people to understand the world?
A map is an essential and distinctive tool for geographers to present spatial data and phenomena. DEF: A graphic depiction of all or part of a geographic realm in which the real-world features have been replaced by symbols in their correct spatial location at a reduced scale.
How do we classify attribute data when making a map?
Before we make a map we need to classify the attributes into categories. Data classification (4 methods) is the process of arranging data into a few classes or categories to simplify and clarify presentation. Each class can be represented with different symbols and colors. There are two purposes of classification: 1) to make the process of reading and understanding a map easier; 2) to show attributes or patterns that might not be self-evident. Natural Breaks method takes all the values and looks at how they're grouped together. The Quantile method tries to distribute values so that each range has a similar number of features in it The Equal Interval method (shown in Figure 12c) creates a number of equally sized ranges of values and then splits the data values into these ranges A standard deviation is a value's average distance from the mean (average) of all values. In the standard deviation method, the breakpoints are based on these statistical values
What is the basic process of making a map in GIS?
Choose a map type, Choose a layout & a template, Display attributes on the map, Classify data, Symbolize the data, Export the map
What are the three basic ways in which points or areas may be arranged?
Clustered: Features are concentrated in one or a few relatively small areas and form groups, and the presence of one feature may attract others. Regular: Features are consistently spaced and regularly arranged. Random: Features exhibit no apparent order in their arrangement. There seems to be some clustering and some regularity, but not enough to distinguish the pattern as clustered or regular.
Give five examples of fields in which GIS is widely applied.
Environmental Science, Political Science, Health Care, Real Estate, Civil Engineering/ Utility
Briefly describe the GIS workflow as a loop.
First, we collect and edit spatial data. Second, we visualize/display the data and perform spatial/statistical analysis to understand phenomena and patterns. Third, we design and produce maps as reported results for decision-makers. (collect -> edit -> analyze-> make a map-> decision) The decisions made will produce effects in the real world. Therefore we collect the feedback and restart the loop to further improve our decisions and policies.
Compare the following: Geographic Information System, Geographic Information Science, Geographic Information Studies
Geographic Information Systems: the technology - "GIS": emphasizes technology and tools for the management and analysis of spatial information (techniques and technology) Geographic Information Science: the concepts and theory - "GIScience": a new interdisciplinary field built around the use and theory of GIS, which studies the underlying conceptual and fundamental issues arising from the use of GIS and related technologies, such as: spatial analysis, map projections, accuracy, and scientific visualization (concepts and theory) Geographic Information Studies: the societal context - "GIStudies": understand the social, legal and ethical issues associated with the application of GI Systems and GI Science (social implications)
What is geospatial data composed of?
Geospatial data consists of two parts: spatial data and attribute data/non-spatial data. Spatial data: Spatial data indicates the location of geographic features, which is usually expressed with geographic coordinates. Attribute data (non-spatial data): describes the properties of geographic features. Examples are statistics, text, images, sound, etc.
What are the three stages of the development of GIS?
Innovation, Commercialization, and Exploitation
What is the difference between the intersect, identity, union, and symmetric difference overlay operations?
Intersecting means only the features that both layers have in common are retained in a new layer. In the Identity operation, an input layer is specified so that all of its features will be retained in the new layer. After a union operation, all of the features from both layers are combined together into a new layer. In symmetric operation all of the features of both layers are retained, except for the areas they have in common (the result of intersection)
What are the basic rules of placing labels for point, line, and area features?
Labels should follow a strict set of rules. Point, line, and area features have difference placement rules. For example, as shown in Figure 9, point labels should be placed above and to the right of point features. Line labels should follow the direction of the line, and curve along with the line if necessary. Area labels should be placed on a gently curved line following the shape of the feature.
Which of the following indices is NOT used for measuring spatial autocorrelation?
Moran's I Geary's C Ripley's K CORRELATION COEFFICIENT R
What is near operation? Give an example using near operation on point features.
Near operations can be used to determine the shortest distance (within the search radius) from a feature in one layer to the nearest feature in another layer. For example, you might use "Near" to find the closest bus stops to tourist destinations or the closest stream for a set of wildlife observations.
What is neighborhood analysis? How do you perform it on raster data?
Neighborhood analysis evaluates the characteristics of an area surrounding a specific location. It is mainly used on raster data. In a raster dataset, neighborhood statistics are useful to obtain information for each cell based on a specified neighborhood. For example when examining ecosystem stability, it is useful to obtain the variety of species residing in each neighborhood in order to identify locations that are lacking variability in the distribution of species.
What types of features will exist in the result of an identity operation over the two layers? The floodplain layer will serve as the base layer where all of its features will remain.
Non-agricultural land inside floodplain and Agricultural land inside floodplain
How do you perform overlay operations on raster data?
Overlay in raster is much simpler - the attributes of each cell/pixel from two or more layers are combined according to a set of rules. The only thing to note is that in order to overlay raster data, the pixels in each layer need to be the same size.
What is spatial analysis? What are the basic operations of spatial analysis?
Spatial analysis is considered to be the crux of GIS, because it includes all of the transformations, manipulations, and methods that can be applied to geographic data. The process turns data into information to support decisions, and reveals hidden patterns The four basic operations of spatial analysis are: Reclassifying maps Overlaying data Measuring distance and proximity Characterizing neighborhoods
What is spatial autocorrelation? What does a positive or negative spatial autocorrelation value indicate?
Spatial autocorrelation describes the similarity of a variable (such as house price) at different locations across space. It is one of the most widely used measures of the degree to which point features are clustered together (positive spatial autocorrelation) or evenly dispersed (negative spatial autocorrelation). Positive spatial autocorrelation means geographically nearby values of a variable tend to be similar: high values tend to be located near high values, medium values near medium values, and low values near low values Negative spatial autocorrelation describes patterns in which neighboring areas are unlike, or where dissimilar values tend to be together.
Compare spatial data vs. attribute data
Spatial data indicates the location of geographic features while attribute data (non-spatial data) describes the properties of geographic features
What is spatial statistics?
Spatial statistics uses spatial relationships (such as distance, area, height, orientation, centrality and other spatial characteristics) between features to understand distributions and analyze spatial patterns in GIS. Unlike traditional statistical methods, spatial statistics are specifically deployed on spatial or geographic data. This provides us a better understanding of geographic phenomena and causes of geographic patterns.
Understand the basic syntax of SQL
Structured Query Language (SQL) format, like a mathematical function. SQL is a specific format that is used to query a database to find attributes that meet certain conditions. *Equal (=): used when you want to find all values that match the query. For an instance, querying for CITY_NAME = 'Madison' will locate all records that exactly match the characters 'Madison'. *Not Equal (<>): used when you want to find all the records that do not match a particular value. For example, querying for CITY_NAME <> 'Madison' will return all the records that do not match the word 'Madison,' that is every city but Madison. *Greater Than (>) or Greater Than Or Equal To (>=): used for selecting values that are more than (or more than or equal to) a particular value. For example, you would use it to find all cities with a population greater than or equal to 100,000. *Less Than (<) or Less Than Or Equal To (=<): used for selecting values below (or below and equal to) a particular value.
Attribute data in vector data model are typically stored into tables, while attribute data in raster data model are stored as values associated with each cell.
TRUE
What is a legend?
The legend tells the reader what the symbols and colors on the map represent. A symbol is a picture on the map that represents something in the real world. Maps use a legend to explain the meaning of each symbol used in the map.
What are the basic requirements when choosing symbols for your map?
The most important requirement for map symbols is that they should be readily recognizable and suited to the scale of the map. We can use symbols with a specific combination of shapes, sizes, and colors to represent anything on a map
What are the map elements?
Title, Fame, Legend, Source/credits, Scale, Arrow (direction), Symbols Essential: Title, Projection, Cartographer, Date Of Production Elements that are optional: Neatlines (a neatline is merely the boundary separating the map from the rest of the page), Inset
What is the standard distance? How is it calculated?
To understand how these parks are distributed around the center we use Standard Distance (SD). sd= √(sum of (x-mean of x)^2/total feature count) + (sum of (Y-mean of y)^2/ total feature count)
What are some useful spatial statistics tools that measure the geographic distributions of features? What are some that analyze patterns and map clusters?
Tools Measuring Geographic Distributions: These identify characteristics of a distribution. They can be used to answer questions like where is the center of a set of features and how they are distributed around that center. (Mean center, median center, standard distance) Tools Analyzing Patterns and Mapping Clusters: These tools can describe spatial patterns and enable us to answer questions like "Are features random, clustered, or evenly dispersed across the study area?" (spatial autocorrelation)
