Massachusetts Institute of Technology - Department of Urban Studies and Planning

11.520: A Workshop on Geographic Information Systems
11.188: Urban Planning and Social Science Laboratory

Presentation Tips, Test Feedback, & Project Work


November 17, 2010, Joseph Ferreira


  • Two Items due on Stellar today:
    • Lab #8
    • Project Mini-Proposal
  • No new lab exercises or homework
    • focus on individual project work
    • especially, do you have appropriate data for useful spatial analysis


  • Initial feedback & discussion of test
  • Project presentation tips (using Cherrie Abbanat's slides)

Test Feedback

  • Test could be an (abbreviated) example of a possible project
    • Test focus: examining bike routes and bike rack patterns in Chicago
    • Project focus: who benefits from bike infrastructure; why are they done in a particular way; what obstacles limit bike usage in American cities
    • Project would require a little more digging and spatial analysis
    • Project could provide context and first step in a longer study
  • Answers will be online by Monday's lab
    • Hopefully, grading will be done by then as well
  • Comments on common issues and difficulties
    • Test data source
      • I forgot to add it to the test! (Shan found the data and provided these URLs)
      • Chicago GIS data:
      • Census 2000 data:
      • Another useful link:
    • Data Queries
      • Queries could be done in Access or ArcMap
        • But, Access table had all of Illinois - need to join with Chicago-area table
      • When dividing to get percentages, zero-demominator can cause problems
        • First select tracts with non-zero entries
        • Or be sure the calculation worked for all but the non-zero entries and put NULL in the rest
      • Join-by-location is easiest way to move census tract ID to the bike rack attribute table
    • Test ambiguities
      • Bike rack 'location' - we intended that you consider each attribute record to be a separate location
        • Even with TotInstall>2 restriction, some records have the same lat/lon locations
        • We accept counts that are either number of rows or (if you tell us what you did) unique lat/lon
      • Bike route count - we intended that you consider each attribute record to be a separate route
        • Records are polylines not individual line segments
        • But, in some cases, multiple records show the same address so distinguishing 'routes' could be tricky
        • We accept counts that are either number of rows or (if you tell us what you did) unique addresses
    • Mapping
      • Hard to get all of Cook County on page while still seeing useful detail
        • Turning off track outline can help
        • Adjusting symbology high/low range can limit size of bike rack symbols
      • More than one classification choice is acceptable
        • Consider 'standard deviation' to emphasize outliers for skewed distributions
        • We recognize that lab machines have trouble with 'histogram' generation in the classification window
        • Histogram always displays in the 'Statistics' window
    • Raster analysis
      • Try using 'zonal statistics' to get census tract average of distance to CBD
        • We held off adding this to the test!
      • The environment settings for ArcToolbox and for 'Spatial Analyst' menu can be different!
      • You could use the 'neighborhood statistics' tool to measure proximity to college students (similar to the senior citizens density in homework #3)
        • This too was beyond the scope of what we wanted on the test

File organization and performance issues for project work

  • C:\usertemp (or C:\temp) are local, desktop and I:\ is not
  • Set LOCAL locations in the environment for workspace and (especially) scratch space
  • Redundancy can be good!
    • Read-only copy of originals (e.g., test10data)
    • Local working copies
      • proj10_working folder that you move from network to C:\usertemp and back
      • Many MXDs: 11.520_proj10_working1.mxd, 2, 3, ...
      • Use Access: 11.520_proj10_working.mdb
    • Multiple windows (especially in 37-312)
      • Use Data Frames with different joins, coordinates, etc.
      • Open multiple ArcMap sessions along with Access and Excel
        • Just keep the file versions straight
        • And you may need to close files if locked for another use
        • Use Data Frames with different joins, coordinates, etc.
  • Refresh issues in ArcMap
    • Sometimes, removing a table and adding it again will add the old version
      • Save ArcMap document, exit ArcMap, and restart - then add table
      • This happens if you edit the table outside ArcMap and do not change the name

Project Presentation Tips

  • Cherrie Abbanat's powerpoint slides
  • Help from the GIS Services group in the MIT Libraries
    • send email to
  • Poster session at Spring APA meeting (in Boston)
    • Plan to submit an E-sized poster from your project
    • We will accept the poster in lieu of a writeup (but you still must do the oral presentation)
  • Monday's Lab (Nov. 22)
    • Work individually on project
    • Discuss project focus and data issues with us
    • Separate 20 minute meeting with undergrads
      • Group discussion about project and CI requirement
      • Meet in 37-312 lab at 2:15 on Monday, Nov. 22

Last modified 17 November 2010 [jf]
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