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Lecture 3

Lecture 3. How does GIS work. How does GIS work?. Maps are stored in computers Databases and Tables Geometry Attributes. How does GIS work?. Categories of reality are divided into layers Countries, States, Cities Parcels of land ownership Roads , Rivers, Lakes, Buildings

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Lecture 3

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  1. Lecture 3 How does GIS work

  2. How does GIS work? Maps are stored in computers Databases and Tables Geometry Attributes

  3. How does GIS work? Categories of reality are divided into layers Countries, States, Cities Parcels of land ownership Roads, Rivers, Lakes, Buildings ZIP codes

  4. How does GIS work? Layers are made up of points, lines, or polygons Cities – points Roads – lines Counties – polygons

  5. Drawing maps Points, lines, polygons, and text Work Main Street Mall Construction Home

  6. Change street layer color and thickness Work Main Street Mall Construction Home

  7. Turn Streets layer off Work Main Street Mall Construction Home

  8. World country layer - polygons

  9. Amelia Earhart’s last flight - lines

  10. Cities (fuel stops) - points

  11. Levels of geography • Country • State • County • City DEMO http://www.marshallco.org/www/maps/images/50seregexpl.jpg

  12. Levels of geography • Block group http://www2.lib.udel.edu/subj/maps/internet/dedo/nnccinc.htm

  13. Levels of geography • ZIP code http://cssr.berkeley.edu/cwscmsreports/maps/showEntriesCountymap.asp?page=Ora

  14. Levels of geography • Parcel • Buildings • Houses

  15. GIS links attribute and spatial data • Each layer has a database table • Each map feature has one record in the table • The table has attributes about the features

  16. One to one: layer and table • One to one: map feature and record

  17. Is your data spatial? • >80 percent of all data has location • “What’s your ZIP code”

  18. My customer database

  19. Here is my store

  20. ArcMap puts customers on the map

  21. Before GIS Just Pens and Paper http://www.census.gov/pubinfo/www/photos/img/lowres/Hist08l.jpg

  22. GIS Power • Just a database • Tools • Analysis • GIS Science and Geography • Geo Statistics • Aids in decision making • Remember “Maps Communicate”

  23. Which 8% of 7000 stores to close? http://money.cnn.com/news/specials/storysupplement/starbucks_closings/CA.html

  24. Where can we add new stores/Delis?

  25. Where can we add new stores/Delis?

  26. 5 steps to GIS analysis

  27. 5 steps to GIS analysis • Frame the question • Get the data • Choose analysis method • Process the data • Look at the results

  28. Frame the question • Where can we put a garbage dump?

  29. Frame the question • Where can we put a garbage dump? • Not on bad soil • Out of the city • Not in a park • Not in a protected area like a forest • More?

  30. Get the data • Color in the unacceptable areas • Can’t locate in dark areas SOILS URBAN PARKS FOREST

  31. Choose analysis method • OVERLAY the layers on top of each other URBAN PARKS SOILS FOREST

  32. Process the data • Color in the unacceptable areas SOILS URBAN PARKS Solution map FOREST

  33. Look at the results

  34. Check out other similar projects http://www.ruralgis.org/conference/2004proceedings/thurs/session4/thurs_4_1_00.pdf

  35. Map Overlay • But what about the protected rats? Rats SOILS URBAN PARKS FOREST Solution map

  36. Before GIS - Paper • Computers speed the process • Databases hold more information than paper • Why GIS? • Faster • Cheaper • Easier • More http://www.census.gov/pubinfo/www/photos/img/lowres/Hist08l.jpg

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