Dear everyone—

Besides learning that we need a “CTPP 2000 FAQs” that I posted yesterday, another thing I learned during Nandu’s absence was that CTPP2000 Part 3 data is STILL confusing and sometimes difficult, despite what we consider improvements in data accessibility over time.  

There are 2 main ways to get the CTPP2000 Part 3 data.

1.  On the CD’s with the .ivt formats.  Extracting data when the data are on multiple CDs is difficult.  Directions for how to extract the data under these conditions are at: http://www.fhwa.dot.gov/ctpp/appxp.htm

2.  From the BTS TranStats webpage. http://www.transtats.bts.gov/databases.asp?Mode_ID=3&Mode_Desc=Highway&Subject_ID2=0

I am interested in improving access to the CTPP2000 Part 3 data using a web-based GIS approach, and recently got a small project approved by FHWA.  I would like YOUR IDEAS!   When we designed the CTPP2000 Access Tool (CAT), we made sure that exporting to .shp files was included, but it was really up to individual users to create analytic maps.  Now that web-based GIS is more robust, maybe it is time to use this technology for CTPP2000, and then it will be ready for the next CTPP based on ACS. (Note:  based on a spreadsheet from AASHTO dated 2/28/07, 37 states have submitted commitment forms for the next CTPP).   

HERE ARE MY QUESTIONS:

1.  What are desired features in a CTPP2000 Part 3 web-based GIS? 

2.  What kinds of mapping capabilities would be useful?

3.  What kinds of tabulations would be useful?   (e.g. counting workers by means of transportation to work by set radii distances from a specific TAZ or tract?)

4.  Would the ability to compare CTPP2000 with LEHD “on the map” 2004 data be useful?

Some of my thoughts (to get you started):

I like the user interface for the LEHD “on the map” program, as it allows users to select origins and destinations, it creates tables for number of workers within defined radii, it creates other “standard” reports for aggregated geographic units.   The LEHD data uses QCEW (previously called ES-202) and federal administrative records and sophisticated disclosure proofing routines that create synthetic data for home-to-work flow pair.  The quality of the underlying QCEW data varies widely by state.  Nonetheless, I like the user interface.  http://lehdmap.dsd.census.gov/

Under e-learning there is a tutorial. http://lehd.dsd.census.gov/led/

A new version of “on the map” software is expected any day now, along with the first release of 2004 data for selected states. 

Judy Clark from the City of Bellevue created some thematic maps using the CTPP 2000 Part 3 data.  This happens to be data with King County Census Tract 228.03 (Microsoft headquarters) as the work destination, because I live in Seattle and thought it would be fun to use as an example.  One map shows number of workers, and the other shows workers per acre.  The first map (number of workers) doesn’t account for the variation in the land area of each tract.  The map using “per acre” is reflecting different land use (more condo and apartment than single family homes, and lot sizes for single family homes). 

Another graph I like is one that Steve Raney from Cities21 did as part of his EPA project in the SF Bay Area. http://www.cities21.org/BABPC/  See .xls file above. 

The budget from FHWA is limited, so I can’t promise that all your ideas will be incorporated into whatever we do.  But, I look forward to hearing your ideas.  Thanks in advance.

Elaine Murakami

FHWA Office of Planning

206-220-4460 (in Seattle)