Introduction
to GIS Modeling
…an introductory course in map analysis
GEOG 3160, University of Denver, Winter 2001
Midterm Study Questions
…see the at http://dev.pacificmeridian.com/basis2/gismodeldisc_frm.htm for an exchange of thoughts about the
questions. The exam will not be curved,
so students “sharing” their good answers will benefit all in their pursuit of
knowledge. I encourage all students to
make good use of the opportunity for group-based learning. It would be a delight to see each student
“max” the exam!!! At least two-thirds
of the exam will be taken directly (verbatim) from the listing of questions.
The exam will be a 1.5 hours,
closed book affair taken over the Internet (honor system) at your convenience—
it will be posted
on the class website by
10:00 am, Thursday, February 8th,
and must be completed by
12:00 midnight, Sunday, February 11th. You
will download the exam (time/date stamped at our website) and email the
completed document to me within 1.5 hours.
Questions on Terminology,
Procedures and Basic Concepts…
1. What are the three fundamental types of map features used in desktop mapping. What is the fourth type that is extensively used in GIS modeling?
2. What is the fundamental “element” used in vector systems? What is the fundamental “element” used in raster systems? Briefly explain the similarities and differences between the two fundamental elements.
3. What is the difference between a “whole” cell and a “partial” cell that are used to define map features in a grid system?
4. Briefly describe the major differences between vector and grid/raster approaches in storing points, lines, areas (polygons) and surfaces.
5. Is an elevation contour in a 2D display of a terrain surface a “line” or “polygon” feature? Explain your answer.
6. Briefly describe the differences among the related fields of “Computer Mapping,” “Spatial Database Management,” and “GIS Modeling.”
7. Is the level of detail increased in a contour map with more contour intervals? Hint: your answer should address both map display (visual) and the data itself (stored information).
8. What is the difference between “lattice” and “grid” data structures? Comment on the differences in the map displays they create.
9. What is the difference between “choropleth” and “isopleth” map data?
10. What are the major differences among a graphics package, a mapping package, a spatial database management package and GIS software?
11. Explain the contention that “map scale” does not exist in a GIS.
12. Identify and briefly describe the four “resolution” factors that need to be considered in fully assessing the level of detail in a map.
13. Briefly describe the procedure for generating the “shape” index (a.k.a., convexity index) used in landscape structure analysis.
14. Briefly describe the procedure for generating the “core area” index used in landscape structure analysis.
15. Briefly describe the procedure for generating the “edge contrast” index used in landscape analysis.
16. What are the differences among the neighborhood variability indices of “richness,” “evenness,” and “interspersion”?
17. Identify and briefly describe the four fundamental processing/analysis levels of a suitability model. Be sure your answer relates these levels to the degree of abstraction from physical fact to decision judgment.
18. Identify and briefly describe the four fundamental classes of map analysis operations.
19. What is the difference between a “raster pixel” and a “grid cell?”
20. The traditional map features include point, line and polygon. Describe how a grid-based system assigns a measure of “size” for each of these map feature types.
21. Identify and briefly explain the differences between the three ways of overlaying maps.
22. Define and describe the difference among the following distance terms…
Simple Distance
Simple Proximity
Effective (or weighted) Proximity
Optimal Path
23. Describe how an accumulation surface is used to determine the optimal path between two locations.
24. Define “narrowness” and describe how a narrowness value is computed for a location within a map feature, such as a meadow.
25. Describe the differences in information contained in the following types of visibility maps…
Simple Viewshed
Visual Exposure Density Surface
Weighted Visual Exposure Density Surface
26. What does the value 0 (zero) indicate on the resultant map when you subtract two proximity surfaces? What does the sign (= or -) indicate? What information does the magnitude of the value provide?
27. What is the interpretation of the minimum value on the resultant map when you add two proximity surfaces?
28. What is the difference between “absolute” and “relative” barriers when generating an effective proximity map?
29. What information is gained when you calculate the slope of a slope map?
30. Identify and briefly describe the two basic approaches for calculating a “fitted” slope value to characterize the overall inclination of a location.
31. What is the difference between an “Optimal Path” map (Stream) and an “Optimal Path Density” surface (Drain)?
32. What information is gained when you use Scan to calculate “coefficient of variation” for a location?
Map Analysis “Mini-Exercise”
questions…
33. Given base maps of Roads and Covertype (Tutor25) develop a simple map analysis that will assign a proximity to roads value to each grid location that is forested. Note: use MapCalc and SnagIt to capture and embed your solution. Be sure to identify the input maps, processing procedure, and output map with an interpretation of its map values.
34. Given base maps of Housing, Elevation and Covertype (Tutor25) develop a simple map analysis that will assign a visual exposure to houses value to each forested location. Note: use MapCalc and SnagIt to capture and embed your solution. Be sure to identify the input maps, processing procedure, and output map with an interpretation of its map values.
35. Given base maps of Covertype and Elevation (Tutor25) develop a simple map analysis that will assign the average slope for just the southerly oriented forested locations. Note: use MapCalc and SnagIt to capture and embed your solution. Be sure to identify the input maps, processing procedure, and output map with an interpretation of its map values.
36. Given base maps of Roads, Elevation and Districts (Tutor25) develop a simple map analysis that will assign the average visual exposure to roads for each of the districts. Note: use MapCalc and SnagIt to capture and embed your solution. Be sure to identify the input maps, processing procedure, and output map with an interpretation of its map values.
37. Given base maps of Housing and Covertype (Tutor25) develop a simple map analysis that will assign the average cover type visual diversity (within a 3 cell radius) for each of the cover types. Note: use MapCalc and SnagIt to capture and embed your solution. Be sure to identify the input maps, processing procedure, and output map with an interpretation of its map values.
Questions on “How Things Work”…
38. Given the following spatial data, which forest parcel (polygon) is most irregularly bounded (has the lowest convexity index)? Note: the numbers will be changed if this question is used.
Parcel A’s perimeter= 5,000m and area= 350,000m2
Parcel B’s perimeter= 3,000m and
area= 420,000m2
Parcel C’s perimeter= 2,000m and area= 260,000m2
39. Using the analogy to tossing an object(s) into a pond, describe how a simple proximity map is created for the following MapCalc commands…
SPREAD RanchMap TO 100 for Ranch_Prox
SPREAD HousingMap TO 100 for Housing_Prox
SPREAD RoadMap TO 100 for Road_Prox
40. Suppose you created a travel-time map (proximity surface) from one location, say a firehouse, to all other locations within a city. Describe how the computer determines the optimal path to a “house on fire” given the travel-time map and the coordinates of the fire (column, row location on the proximity surface).
41. In the Radiate command for calculating visual connectivity, what how do the options “simply,” “completely,” and “weighted” affect the resultant map?
42. Referring to the following diagram, if the cell size is 100 meters, what is the Simple Distance from point A to point B (in meters)? What is the Effective Distance (in minutes) considering the relative friction factors indicated in the upper right corner of each grid cell (friction units in minutes; -0.0 indicates an absolute barrier)? Note: the numbers will be changed if this question is used.
43. Referring to the following diagram, which points (B,C and/or D) can be seen from point A? …given 1) that the elevation values (in meters) are indicated in the upper right corner of each cell, 2) that the grid cell size is 100 meters, and 3) that the square root of 2 is 1.414. Note: the numbers will be changed if this question is used.
44. What is the maximum slope (center to eight adjacent neighbors) for the 3x3 window composed of elevation values shown below? …given 1) that the elevation values (in meters) are indicated in the upper right corner of each cell, 2) that the grid cell size is 100 meters, and 3) that the square root of 2 is 1.414. Note: the numbers will be changed if this question is used.
45. What is the “Edginess Index” for the following boundary cell (outlined in the center) of a forest parcel (forest= 2; non-forest= 0)?
