GIS for Week 4 (2/15)

Submitted by Andy Anderson on Friday, 2/11/2011, at 9:49 AM

By Tuesday, February 15, at 1 PM, please do the following exercises:

  1. On whichever Windows computer you're using, set up the assignment:
    1. Map the network drive \\storage\colq-32 (if necessary).
    2. Start up the program ArcCatalog. In addition to letting you make changes to individual files like adding their projection, ArcCatalog makes it simpler to copy shapefiles and other GIS files by displaying all of their pieces as a single item. For example, the set of files

      states.shpstates.sbnstates.sbxstates.shp.xmlstates.shxstates.dbfstates.prj

      would all appear in ArcCatalog (as well as ArcMap) as the single item states.shp, which you can easily copy, cut, and paste amongst the folders in the Catalog Tree on the left side of ArcCatalog (usually). In ArcCatalog:
      1.  Make a connection (if necessary) to the Desktop of your computer.
      2.  Make a connection (if necessary) to your own folder in \\storage\colq-32 .
      3. In your colq-32 folder, locate the folder Scanned Maps, find your map document from Tuesday's class with the Cambridge boundary file and the partially georeferenced HOLC map, and double-click on it to open it.
      4. Verify that the map document is using relative pathnames; change it if necessary, save it, and quit.
    3. Return to ArcCatalog and:
      1. Right-click on the folder Scanned Maps, and copy it.
      2. Select the Desktop folder and paste (this will make your work faster).
      3. Rename this new folder Assignment Week 4.
  2. Since the National Historical Geographic Information System, http://nhgis.org/ , can take a while to prepare its data, start with that. The HOLC map is dated 1938, so you should get 1940 data.
    1. Download a census tract shapefile.
    2. Request data for:
      1. General Population Data => Core Demographics => Race => Occupied Dwelling Units by Tenure by Race (NT28);
      2. Buildings => Housing => Value => Median Value of Homes for Which Value was Reported (NT36)
    3. Make sure you download both the GIS CSV file and the ASCII codebook. Give the files a relevant name, e.g. “MA_Census_1940_Housing”.
  3. Continue georeferencing your HOLC map using the instructions on the handout.
    1. Load the set of control point links that you saved at the end of class.
    2. When georeferencing with CambridgeCityBoundary.shp, remember that you need to focus on its corners, and be aware that the boundary in the Charles River is probably not well-defined. You shouldn't do more than ten control points here.
    3. When you've run out of obvious boundary points, add the shapefile CambridgeMajorRoads.shp. Symbolize it in a clear way. You can use its street intersections as well as intersections with the Cambridge boundary, e.g. the middle of bridges across the Charles River (though roads along the river will generally be more accurate). Fill in roughly 20 or so well-distributed points on the edge and in the interior.
    4. Add the shapefiles CambridgeRail.shp and CambridgeSubwayLines.shp; these are relatively small files but may allow for a few more significant points where they don't follow major roads. Again symbolize them in a clear way.
    5. Save your Link Table in the folder Assignment Week 4.
    6. Set the Transformation: to Spline.
    7. Rectify your image, saving it as a JP2 file in the folder Assignment Week 4,  with a compression of 50 and bilinear resampling.
    8. Add the rectified image to your map and set its NoData symbolization to No Color.
    9. Turn off the original image (this should make it faster).
    10. Save your map document.
    11. Menu File and then Export Map…, and in the resulting dialog locate the menu Save as Type: and choose PNG; name the file appropriately and then navigate to your folder “Assignment Week 4”  and click the button Save.
    12. Roughly how much of Cambridge falls into the four different HOLC housing grades (expressed as fractions of the total graded area)? Write your answer in a text file “Answers” in your folder Assignment Week 4.
  4. Using the  census data for 1940:
    1. Add the tract shapefile to your map. 
    2. Consider the ratio of total owner-occupied housing to total tenant-occupied housing:
      1. Use Excel to add columns to the housing CSV file and calculate these values. Resave as CSV or as Excel.
      2. Join the housing table to the tract shapefile.
      3. Symbolize this ratio.
      4. Menu File and then Export Map…, and in the resulting dialog locate the menu Save as Type: and choose PNG; name the file appropriately and then navigate to your folder “Assignment Week 4”  and click the button Save.
      5. How does this ratio compare to the HOLC housing grades? Write your answer in a text file “Answers” in your folder Assignment Week 4.
    3. Consider the ratio of Negro-owner-occupied housing to White-owner-occupied housing:
      1. Symbolize this ratio.
      2. Menu File and then Export Map…, and in the resulting dialog locate the menu Save as Type: and choose PNG; name the file appropriately and then navigate to your folder “Assignment Week 4”  and click the button Save.
      3. How does this ratio compare to the HOLC housing grades? Write your answer in a text file “Answers” in your folder Assignment Week 4.
    4. Consider the value of housing:
      1. Symbolize this quantity.
      2. Menu File and then Export Map…, and in the resulting dialog locate the menu Save as Type: and choose PNG; name the file appropriately and then navigate to your folder “Assignment Week 4”  and click the button Save.
      3. How do these values compare to the HOLC housing grades? Write your answer in a text file “Answers” in your folder Assignment Week 4.
    5. Don't forget to save your map!
  5. Drag the folder “Assignment Week 4” from your desktop to your folder in \\storage\colq-32.
Due Date: 
Tue, 02/15/2011 - 13:00