Office of Planning, Environment, & Realty (HEP)
Compiled notes from the CTPP List serv.
For your reference, here are a few e-mails that were posted to the CTPP Listserve. If you encounter problems in converting TIGER/Line to your GIS, please post your question to the CTPP Listserve at email@example.com. To subscribe to the listserve, please send e-mail to Ed Christopher, FHWA at firstname.lastname@example.org.
Procedure: Incoming E-Mail from Daryll Scott, South Western Regional Planning Agency
I used the following procedure to create the urbanized area GIS layer for the Bridgeport-Stamford-CT, NY urbanized area. Because I already had Census Blocks in my GIS system, I only wanted a table that would allow me to join the urbanized area information to the Census Blocks. Perhaps the following procedure and sample file will help others generate maps of the new urbanized areas.
Afterwards, display the query in datasheet view. At this point, I would compare the number of records in the table to the number of blocks in the cooresponding GIS layer. I would also check to make sure that the urbanized area names make sense. If there are any irregularities, you will need to correct mistakes in the query.
If the results are correct, then you can join the results to the Census Blocks in GIS software. The table can be exported to a dBase IV file or text file. In some cases, you can connect the Access database to the GIS software directly or through ODBC. Once the join is performed, you can perform spatial aggregation to get the anticlimactic urbanized area GIS layer.
Some software specific Issues:Arc/Info
When I ran TIGER Reader in ArcView and chose "Urbanized Areas 1990" as the field to extract, the results matched up exactly with the Arc/Info converted files. Has anyone else noticed this? It appears that TIGER Reader may be doing the conversion correctly, even though the field is named incorrectly.
I found the TIGER Reader script by clicking ArcScript on the ESRI main page and then running a search for "tiger" and narrowing the search to the Avenue language. The URL line from the search is http://arcscripts.esri.com/scripts.asp?eQuery=tiger&eLang=2&eProd=&eRecs=10
One way to depict urban blocks (and thus get to an urbanized area or urban cluster) in a shapefile with ArcView is reviewed here: http://proximityone.com/urbrural.htm and also here http://proximityone.com/cen2000.htm#urbrural in a different context.
I used the TIGER Reader extension for ArcView and found the same thing. It reads the 2000 UA, but labels the field UA90, and it truncates the last digit (gives only 4, should be 5) of the UA code.
I loaded in the 1990 Urban Area .shp file as well, (downloaded from census website http://www.census.gov/geo/www/cob/ua1990.html yesterday) to be certain. The area I was looking at is a UA in 2000, but wasn't in 1990. So this confirmed that the TIGER Reader extension is reading in the UA 2000 boundaries, it just labels them UA90.
Other commerical Vendors: Some commercial vendors have develop tools to convert the UA TIGER/Line file into other GIS platforms. An example is http://www.gistools.com/
I used TransCad and opened TIGER file for our county and then imported "Census Urban Areas" This gave my new urban boundary.
I used Maptitude's TIGER/Line Import function without any problem. The TIGER Version is 2000. Feature to import is "Census Urban Areas." I converted the projection to NAD83. Now, I have to join all 9 Counties together and get pertinent Census 2000 Block or Block Group demographics for further analysis. I would welcome any suggestions as to steps for doing this and procedures and considerations for revising the Metropolitan Planning Area.
CALIPER's SF 1 Data CDs, available by state for $195 each, have the full SF 1 tables for each summary level down to Census blocks. The State Data CDs, also available by state for $195 each, have geographic files for all of the summary levels within a state, down to Census blocks, plus other geographic files such as streets.
Maptitude and TransCAD come with nationwide geographic files down to Census tracts, and the demographic profile for SF 1 for each of those summary levels. For more information on geographic and Census 2000 demographic data available from Caliper Corporation, visit (http://www.caliper.com/ovudata.htm).
CENSUS BUREAU: INCOMING FROM Bob LaMacchia, Geography Division, U.S. Census Bureau
The alert eyes (and computer processing skills) of one of the many state Department of Transportation folks processing the UA Census 2000 TIGER/Line files has discovered that the 1990 Urban/Rural code on Record Type S in the UA Census 2000 TIGER/Line files is in error. We have determined that this effects over 1000 counties, and are now preparing a notice for our web site.
We also are discussing how to best resolve this situation. The error overstates the extent of the 1990 urban classification in the affected counties -- some polygons are classified as 1990 urban when they should have been 1990 rural. The 2000 UA/UC codes and Urban/Rural codes are correct, as is the 1990 UA code.