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. I am a busy person and apologize in advance
for the hastily written directions.
* Download UA TIGER/Line files.
* Rename tgrxxxxxx.rta to tgrxxxxxxa.txt
* Rename tgrxxxxxx.rts to tgrxxxxxxs.txt <<ua2000_example.zip>>
* Rename tgrxxxxxx.rtc to tgrxxxxxxc.txt
* The xxxxxx is the state and county fips code.
* Open the Access file.
* Choose File -> Get External Data -> Import...
* Select the tgrxxxxxxa.txt text file and click the "Import" button.
* Click the "Advanced" Button.
* Click the "Specs..." Button.
* Choose the "Tgr09001a Import Specification"
* Click "OK".
* If you do not mind Access automatically inserting a primary key, simply click
"Finish". Otherwise, work through the wizard and choose the appropriate
* Repeat the above process for the record type s and record type c files. Use the
"Tgr09001c Import Specification" for tgrxxxxxxc.txt and "Record Type S
Import Specification3" for the tgrxxxxxxs.txt.
* At this point, all the necessary information is now in Access.
* Copy the "UrbanRuralBlocks09005" query to a different name.
* Edit the query in SQL view and rename the table names to match the table names of the
tables for one county.
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.
South Western Regional Planning Agency
Stamford Government Center
888 Washington Blvd., 3rd Floor
Stamford, CT 06901
Tel: (203) 316-5190
Fax: (203) 316-4995
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