Getting GIS-Ready Census Data
The resources the Libraries has at this time that are easiest to use for compiling GIS-ready Census data are CD-ROM products from GeoLytics.
Finding the Right Resource
Click here to see our current holdings of GeoLytics products. More recent years have separate discs for long form (sample) and short form (100%) data; the 2000 set has separate discs for block-level data.
All products are available in D. H. Hill; some are also available at the Natural Resources Library. Ask at the respective Reference Desks to retrieve the discs you need. The discs are for in-library use only--they do not circulate and may not be copied. Each disc of multi-disc sets contains several states; check the disc labels for the state(s) you need.
Steps for Generating a Report and Shapefile
1. Save your file Always start by saving your request. The filename must have eight or fewer characters not including the three-letter file extension, .req. This practice will prevent you from overwriting data when you run successive reports, as well as keep your files where you can find them when you export to shapefile format.
>>File>>New Request
(NONAME is the default filename.)
2. Select your geography(ies)
A) >>Area>>Geographic Area>>[whatever overarching geography you need]
First pick the geographic level you want to get to. A screen will open that allows you to choose the specific ones you need. You may choose geographies at that geographic level across states, counties, etc., but you cannot select multiple geographic levels at one time. If you need some tracts and some counties, you’ll have to run a separate report for each geographic level.
B) >>Subarea>>[your desired level of smallest geography]
Note: You must use the Subarea menu if you want to produce a map or shapefile.
This menu's other use is to select all geographies within another, for example, all block groups within a state (or states). You must first use the Area menu to choose the larger, organizing geography, in this example, State. Then in the Subarea menu select which lower geographies the program should compile, here, Block Group. (This example would take a LONG time to process into a map.)
If you just want to create a shapefile and don’t want the lower level geographies, choose the same geographic level that you did in the Area menu.
You won’t get another popup screen once you click on your selection but if you click on Subarea again you’ll see a checkmark next to your choice.
C) >>Run>>All Counts Report
If you just want to browse available variables, select your geographies as above, then use the Run menu to select an All Counts Report. The report is far more readable than the variable selection screen below.
3. Pick your variables
>>Counts>>Display
If you’re not familiar with Census data you may want to use >>Search>>Counts to look for variables with particular keywords in them. The search mechanism is not very sophisticated, though--it will only search for an exact string, so that if you search for "rent" you'll get everything with "parent" as well as housing variables. Also, searching has been known to cause the program to crash.
>>Click on the buttons at the upper left corner to display all table titles.
The categories represented by the buttons are arbitrary, a construction on GeoLytics’ part, not the Census Bureau’s. Clicking on the buttons makes the table titles display in the first frame.
>>Highlight a table title to see the individual variables available from it in the second frame.
>>Highlight a variable to select it, so that its number appears in the third frame.
NOTE: Deselecting items in the first or second frame automatically removes them from the third!
Control- and Shift-click do not work in these products but you can select multiple non-continuous items just by clicking (no special keystroke necessary). Multiple continuous items can be selected by clicking the first and last items and then clicking the Select Between button to the lower right.
Caution: It’s easy to select individual variables out of a table. Be sure to also select the Total for each table—you’ll need it to calculate percentages because different tables are based on different “universes” or groups of population. Run a Summary to see the universe for a given table (it will also be listed in the .doc file after you export to shapefile format).
>>Click Done to continue.
4. Run the report
>>Run>>Map
5. Export to shapefile format
>>File>>Export>>to Arcview’s shape
6. Capture files
The program places exported files in the installation directory by default unless you saved your request to a different directory when you started. Then your map files will be put in whatever directory you selected. To use the layer in GIS, you need to capture four files here. They will all have the same filename (whatever you named it) with the extensions .doc, .dbf, .shp and .shx. (The .req file is simply the parameters of your GeoLytics request.) Resave these four files to the directory where you keep your other data layers and you will be able to add the layer to your map as you normally do.
Contact the Data Services staff if you have problems or questions.
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919-513-4433