Discussion Questions for Chapter 3

10/6/2004

1. Why do we build representations?
2. What is Tobler's First Law of Geography?
3. Geographic data link place, time, and attributes.  Explain.
4. Explain Gore's concept of a Digital Earth.
5. Explain what tradeoffs must be made to create a Digital Earth since the Earth is infinitely complex and computer systems are finite.
6. What does a spatial resolution of 10 km mean?
7. The range of attributes in geographic information is vast.  What nominal, ordinal, interval, and ratio attributes?  Give examples of each.
8. What is the discrete object view?
9. Give examples of zero, one, and two dimensional geographic objects.
10. Explain the other main type of geographic representation called the field view and compare it with discrete representation.
11. The ability of a GIS to handle 3D objects is limited.  What is a 2.5D representation? Compare 2.5D to 3D representation.
12. There is a strong association between rasters and fields.  Explain this statement and explain the raster method of representing geographic data.
13. One type of raster data comes from satellites.  Explain how these data are collected and why they are raster.
14. How are point, line, and polygon objects represented in the vector system?
15. Explain the difference between the largest share rule and the central point rule in raster representation.
16. Explain the man value assignment rule in raster representation.
17. What are some of the advantages of raster and vector systems?
18. What is meant by the scale of a digital map?  Why is this conceptually different than the scale of a paper map?
19. What are DRGs and DLGs?