----- Original Message -----
Sent: Thursday, June 21, 2001 12:09
PM
Subject: [CTPP] Attention: Agencies that
want to define new TAZs or alterTIGER/Line 2000 TAZs.
Agencies have written to the CTPP Working Group asking:
If
TAZs defined in TIGER/Line 2000 can be altered/changed.
Can an agency
submit new TAZs in Urban areas based on TIGER/Line 2000 geography for CTPP
2000?
The CTPP Working Group met on June 14, 2001 to discuss these
issues. We decided that agencies could define new TAZs or alter TAZs in
TIGER/Line 2000 and obtain CTPP 2000 data reported for the new TAZs.
However, agencies must use Census 2000 tabulation blocks to build new TAZs or
alter existing TAZs. In effect, an equivalency file between census
blocks and TAZs will be built and used, as was done in previous
censuses.
However, due to processing issues and schedule considerations,
agencies wishing to do this should note the following:
1. Cost: To
change TAZs or define new TAZs, agencies must separately contract with the
Census Bureau, Journey to Work Branch, and work out a process and cost for
defining and obtaining CTPP 2000 data based on the new TAZs.
2.
Schedule: CTPP data will be processed for those agencies after the Standard
CTPP 2000 products are released for the whole country. Currently, the
expected completion date for CTPP 2000 is June 2003.
3. Exclusion of the
changes from TIGER/Line database: There are no plans or processes in place to
include new TAZs in the TIGER/Line database. Thus, the changes will not
be reflected in TIGER/Line 2000 and it is unlikely that new TAZs will be
inserted into TIGER until the next round of TAZ updating, the date of which
has not been scheduled.
For more information, please contact Phillip
Salopek, Census Bureau, Population Division (Journey to Work Branch) at
301-457-2454 (e-mail:
phillip.a.salopek@census.gov).