Lance: Census TAZs in 1990 (and in 2000) were a function of census blocks, not tracts. You will need to find a Tract shape file for 1990, and perform aa geographic equivalency (using operations such as "intersect" etc...) to create an "equivalence" file. 1990 Census TAZ shapefile is posted at http://transtats.bts.gov/DL_SelectFields.asp?Table_ID=1258&DB_Short_Nam…1990. Select state = Missouri, and MPO = St.Louis. You should get a zipped file of all the geographies used in the 1990 CTPP for the "urban element." There was a CBD definition in 1990 data, and those shape files are also posted at the same URL. Thanks Nanda ________________________________ From: ctpp-news-bounces(a)chrispy.net on behalf of Huntley, Lance Sent: Mon 10/8/2007 11:53 AM To: ctpp-news(a)chrispy.net Subject: [CTPP] 1990 TAZ boundaries - Question for the Listserv Hi, I have been asked to find out if there is an equivalency file for 1990 TAZ geography to 1990 Census tract geography. I am not aware of anything like this but thought this listserv would be a good place to ask. Essentially the person asking the question has 1990 TAZ data and wants to link it to corresponding 1990 Census Tract boundaries. He comments in his request that there is something called a "Commuting Zone" in the 1990 geographies he has looked at, but isn't quite sure if this is a TAZ. Thanks in advance for any help received on this request. Lance Huntley East-West Gateway Councils of Government St. Louis, Missouri _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news