MABLE/Geocorr (Version Index)
These geocorr web modules allow the user to obtain geographic correpondence files (aka "crosswalk files",
"correlation lists", etc.) for dozens of geographic layers for the United States (50 states + DC).
The various applications are nearly identical in what they do, but vary in terms of the vintage of the MABLE
datbase being accessed.
Click on the version name to be taken to that application.
Geocorr14. This is the current production
version that works with the latest available data through 2014.
Geocorr12. This is an earlier
version that works with 2012 vintage data. Why anyone would use this version instead of 2014 is a mystery to us
but the stats show it is the most frequently accessed version.
Geocorr2k. This is the
version that works with geography from the 2000 census (with some updated fields as recent as 2008).
Geocorr90. This is the
version that works with geography from the 1990 census. This is the original.
Videos of 4 sample runs.. These
examples were created circa 2010. They access the 2k version of MABLE/geocorr but the concepts still apply to any
The orginal help file..
Quite possibly the oldest living document on this web site. Originally written circa 1996 to document this new application. We have not seen fit to change much of anything
since then. It will never win any style points but it is still the best resource to use when trying to understand how
geocorr does what it does.
Sample queries 2012 .
These don't show and tell like the video modules do, but they take a lot less time to view and they can be easily used
as templates to do your own queries. You should begin by following links to the htm files (the lines in bold with
Description filled in). See the Readme.html file for tips.
Powerpoint presentation on M/G at the 2015 Missouri GIS conference. 36 slides.
2006 Power point. This
venerable 39-slide presentation is still useful. A revised version is planned.
Data Allocation Using Geographic Equivalency Files
is a tutorial illustrating how geographic equivalency files can be used to allocate data summarized at one geographic
level to another (source to target). For techies only.
Each of these geocorr versions has its own link to a MAGGOT file. The Master
Area Geographic Glossary of Terms pages provide brief descriptions of the
geographic layers available for that version of MABLE/geocorr. (The link appears just below the Select State(s) box on the goecorr form).
The MABLE databases are almost entirely based on the Census Bureau's TIGER databases. These do not exist prior
to 1990 and so there is almost no chance that we shall ever see a geocorr80 or geocorr70. But a geocorr20 is
Each version of MABLE is based on its own set of census blocks (1990, 2000 or 2010). There is currently
no version of geocorr that can work across these database to produce correlations across time. (So you can't use geocorr to
create a tract-2000 to tract-2010 equivalency file.)
When doing large extracts (usually this means when doing all states at once) use the Output Options section
to turn off the report file output. Generating such large html files wastes time and space.
For data geeks only: the MABLE databases are collections of state-based SAS data sets, that can be directly accessed using the
MCDC's Uexplore/Dexter modules. Each state has 4 SAS data files with <stab>v (alv, akv, ...) being a SAS
view that merges the other 3 together to give you all the geocodes at the block level for that state. Dexter can provide output
in SAS data set and dbf formats as well as csv, html and pdf.