Goal: Create thematic map of PERCENT of WORKERS who DRIVE TO WORK ALONE.

Share Screen:  http://mit.webex.com/meet/jf

Issues:

• Overview of steps in the lab:
  • Data and computation needed to map the percent of workers driving to work alone:
  • 2010 census block group boundaries for Eastern Mass
  • Census counts for workers aged 16 and over who do/do-not drive to work alone
  • Compute percentage who drive to work alone
  • Join census percentages to block group boundaries and map thematically
  • Get the needed files into C:\temp\...
  • Gain experience working with a personal geodatabase and with MS-Access
  • Extract Eastern Mass census block groups in Mass State Plane coordinates
  • Potential problems with various spatial selection methods
  • Could you select by attribute?
  • Find and extract the appropriate ACS variables at the census block group level
  • Construct your drive-to-work indicator (with appropriate block group identifier)
  • Join your drive-to-work indicator to the Eastern Mass map
• Using ACS data
  • Today's files are big enough (36 MB) to worry about organizing useful copies in C:\temp
    • Copy entire directory Q:\data\lab3_ACS_09_13 to a LOCAL drive (e.g., C:\temp)
  • Start 11188_lab3_ACS_09_13.mxd from your local copy
  • Unzip the geodatabase
  • Do this copying while you are reading the lab as the download will take a while
  • At end of day, copy entire C:\temp\lab3_ACS_09_13 directory (with saved ArcMap documents) to I:\ or a USB drive
  • Finding the desired variable
    • What ACS variable? Using the ACS appendices and table templates
  • Normalizing counts to compute percents:  divide counts by the appropriate 'total'
  • Where to get data?
  • ACS products (and margin of error estimates)
• Some data tables are already loaded into MS-Access for your convenience!
  • lab3_ma.mdb has all the ACS data that you need (except for X08Short table that you import from Excel into the database)
  • Why use MS-Access?
  • Why not use ArcGIS or a spreadsheet instead?
• DEMO During-lab
  • Open 11188_lab3_ACS_09_13.mxd
  • Use ArcCatalog to examine geodatabase: ACS_2013_5YR_BG_25.gdb
  • Export/import geodatabase files and MS-Access tables
  • 'Select by location' options: finding block groups in certain counties
  • Construct MS-Access queries - and avoid divide by zero problems
  • Use MS-Access tables in ArcMap
• Data sources: Census, Social Explorer, the MIT Geodata repository, MassGIS, something else?
• Making professional looking maps
• The ArcScript for ColorBrewer files
• TIGER/Line cartographic boundary files
• Dealing with odd ocean/water shapefiles
• Guide lines in Design view