CommunityViewer & Census 2010 LUCA Program

LUCA and the TIGER/Line Shapefiles

This summer the Census Bureau announced that the 2006 Second Edition TIGER/Line files will be the last of the TIGER/Line files and that new geographic resources will replace the TIGER/Line files (see Census notes). The TIGER/Line files are of critical importance not only due to their role for the decennial census and related programs but also for a myriad of GIS applications -- as the source for many types of landmark point shapefiles; streets, rail, streams and other line shapefiles; and block, tract, place, county, congressional district and many other wide-ranging polygon boundary files. Among the new Census Bureau public use geographic resources will be the TIGER/Line shapefiles (see Census notes).

The target date for the first set of TIGER/Line shapefiles is Fall 2007. TIGER/Line shapefiles will be distributed to participants in the Census 2010 LUCA program. The current schedule for all of the counties to be completed through the MAF/TIGER Accuracy Improvement Project (MTAIP) is April 2008. The "2007 TIGER/Line shapefiles First Edition" will include some counties that have been updated since the release of the 2007 Second Edition TIGER/Line files (TGR2006SE). 1,871 counties of the total 3,219 counties had been updated with the TGR2006SE release (see list). This means, among other things, that some LUCA participants will receive TIGER/Line shapefiles for areas where the MAF/TIGER Accuracy Improvement Project (MTAIP) has not been completed.

MAF/TIGER Accuracy Improvement Project (MTAIP) Updates
Planned Production for FY 07-08 Weekly Status
http://www2.census.gov/geo/maps/mtaip_status/FY07_08_production.pdf
Planned Production Source for FY 07-08 Weekly Status
http://www2.census.gov/geo/maps/mtaip_status/FY07_08_source.pdf
Completed Production Weekly Status
http://www2.census.gov/geo/maps/mtaip_status/completed_production.pdf
Local Street Centerline Data Evaluation Weekly Status
http://www2.census.gov/geo/maps/mtaip_status/centerline_evaluation.pdf
There is a time lag of several months between the MTAIP completion date and th TIGER/Line public use data availability date.

With release of the TGR2006SE, Georgia counties where MTAIP has been completed are shown in green in the following map. Counties where MTAIP had not yet been completed appear in beige.

(click for larger view -- press F11 key after display)

As of mid-September 2007, Census does not identify the counties where TIGER/Line shapefiles will be released for counties where MTAIP has been completed since release of TGR2006SE. Thus, TIGER/Line shapefiles provided to LUCA participants for some (possibly all) non-completed MTAIP (and some completed) counties could be seriously lacking for accuracy, dated/incorrect with respect to Census Feature Class Codes, and have many road segments missing (a result of being dated and older quality control processes).

While updating address lists and address counts is of critical importance, LUCA participants should carefully assess spending resources to update non-completed MTAIP county TIGER/Line shapefiles. Use of those resources on updating the address list will have much better pay-off. However, for counties with MTAIP completion it is equally important to update the address lists and the TIGER/Line shapefiles.

Comparing Locally Developed Shapefiles with TIGER/Line Shapefiles. Many counties and metros have developed their own high quality street centerline shapefiles (see link in above table). Even though possibly originally based on the TIGER/Lines files, these shapefiles will substantially differ with the most current version of TIGER/Lines shapefiles. This is a result of factors including that segment locations are based on different latitude-longitude vertices. Locally developed street shapefiles seldom carry left and right side segment attributes such as census block codes. These differences limit how well locally developed streets and related shapefiles can be used for the LUCA address list or Census supplied shapefile updates.