Geographic Information Systems

GEOL-4611   Fall 2014

Review Sheet for Lecture Test #1

 

GIS-Past, Present and Future (Readings: Chapters 1 & 9 and Labs #1 & 2)

1. What is the basic definition of a Geographic Information System?  List and describe the three major components of any ‘system’.

2. How does GIS software provide ‘integrated functional capabilities’?  List and describe each of the major functional capabilities.  What is the most important software component relative to speed and efficiency?

3. Why is planning the most important component of the GIS procedures?  List and describe the steps involved in the planning process.  List and describe the other steps in a GIS project (other than planning).

4. Define and give examples of both spatial and nonspatial data.  What are the four basic types of spatial map data?  Give examples of geographic features that are represented by each type.  How is each type of spatial data stored in a computer?  Compare and contrast vector and raster data.  When is it better to use raster data even though it requires much greater storage space and takes longer to access? 

5. Name and describe an application for GIS in each of the following fields:  Resource Management, Marketing, Heath Care, Utilities, Mineral Exploration, and Emergency Services.

6.  Define cartography.  How has cartography slowly evolved into GIS?  How did the earlier GIS software and hardware differ from the modern versions?  Describe some of the predicted future trends for GIS.

7. Compare and contrast the following software packages: AutoCAD, GRASS, MapInfo, XMap and ArcInfo.  What is ‘open source’ GIS software?

8. Define the following terms and acronyms: DBMS, GIS, GPS, vector, raster, cartography, GUI, orthophoto, workstation, metadata, projection, digitizer, topology, theme and union.  Note: Some of these terms are found in Lab #1.

 

Cartography Basics – Scales, Projections, Datums & Coordinate Systems 

(Readings: Chapter 2 and Lab #3)

1. Describe the two basics types of map scales.  List the three most common scales used by the USGS for paper maps.  Be able to determine the best map scale if given the size of the study area and the size of the required paper map.  For example which scale would you use for a study area of 100 by 100 kilometers and a paper map of 1 meter by 1 meter?  Which scale would be best if the study area increased to 2,000 by 3,000 kilometers and paper map size remained 1 meter²?  

2. Why is GIS described as ‘scaleless’?  How is this helpful and problematic? 

3. List and describe the three major scale problems encountered in GIS.  How are they commonly corrected or prevented?

4. What is unprojected spatial data?  Why is it more accurate and often better to use than projected data?  What are the basic units of unprojected data?

5. Why are latitude and longitude measurements commonly converted to decimal degrees?  Convert the following into decimal degrees: 17°45’N, 65°49’15”S, and

125°12’16”W. Convert the following into standard latitude and longitude (degree, minutes and seconds) measurements: 26.2356°N, 145.23°W, and 87.231223°S.  If one degree at the equator is equal to 111.24 km, determine the resolution of the last decimal place for each of the above decimal degree measurements.  

6. Why must trigonometry be used to calculate distances between latitude and longitude measurements?  How does GIS calculate these distances so rapidly?

7. Describe and draw simple sketches of the following basic projection types: planar azimuthal, polar azimuthal, cylindrical, and conic.  Make a chart that describes construction techniques, advantages, disadvantages, applications and common examples for each type.

8. What is Tissot’s Indicatrix?  How and why is it used?

9. What are datums and why are they used?  Describe how the North American Datum of 1983 was generated.  Why was the WGS84 datum created and how is it used?  Which geometric shape best describes the earth?  Explain.

10. Describe the benefits and disadvantages of using the geographic coordinate system.

11. For each of the following coordinate systems, describe how they are generated, which type of projection system they use, on which maps they are used, and their advantages and disadvantages: UTM, Military Grid and State Plane Coordinate System.

 

Spatial Data Models and Structures (Readings: Chapter 3 & 4)

1. What is a spatial data model?  Compare and contrast spatial data models and structures.

2. Describe the different types of spatial data relative to dimensions and continuity.  Give examples of each type.

3. Describe how most data is stored in computers.  Why is text data most commonly stored in ASCII files?

4. Describe the advantages and disadvantages of vector data. 

5. Define, compare and contrast spaghetti and topological vector data structures.  What are the advantages and disadvantages of each data structure type?

6. What is a Triangular Irregular Network data structure?  How and why is it used?

7. Define and list some of the uses of the following vector data formats: DLG, Postscript, HPGL, DXF, TIGER and e00.

8. Describe the advantages and disadvantages of raster data models.

9. Why are compressed raster data structures more commonly used than full raster data structures?  Describe how the following compressed raster data structures are constructed: run-length encoding, quadtrees, octrees, and Freeman code. 

10. Define and list some of the uses of the following raster data formats: TIF, GIF, JPEG, and DEM.

11. Define the following terms: bit, byte, kilobyte, megabyte, gigabyte, terabyte and CAD.

12. Describe how the map shown below can be stored as either a raster or vector model.  When would it be more beneficial to use either model?