----------------------------Original message----------------------------
Does anyone know whether there exists a digital list showing
the relationship between 1960 and 1970 census tract numbers
for Chicago?
 
The _much_ larger issue is: Is anyone out there working on (or have
available) historical census boundary files for the United
States in a familiar GIS format? What one would want would be not only
boundary files for each decade but census data for succeeding decades
consolidated to earlier decade boundaries--plus correspondence lists
when tract numbers or other geocodes have changed. In other words, Tiger
and summary tape files for each decade--plus decade-by-decade data for
succeeding decades.
 
Here at the U of C Map Collection, we created boundary files for
Northeastern Illinois/Northwestern Indiana for 1980, including some 1990
data consolidated to 1980 boundaries. It was a lot of work--not the
sort of thing that should be done twice.
 
Thanks for any help.
 
Chris Winters
University of Chicago Library
Internet:        [log in to unmask]