The issue discussed in the email below has been resolved. A new file with TAZ data for
workplace TAZ with zero resident populations has been uploaded and incorporated into the
CTPP Data Access Software. The data has been field checked and deemed reliable, in as
much as small area data are reliable, please pay attention to the large Margins of Error
associated with small estimates.
"Until approximately January 2014, the data set available does not include workplace
data for TAZs with zero (0) populations. This means that any TAZ which consists solely of
a special generator (i.e., an airport, a shopping mall, a business park, the pentagon,
etc.) does not have its associated workplace data or flow to it available. This is being
rectified and a new dataset will be released around January, 2014 that corrects that
problem. Fortunately, the data is available at tract even for zero pop tracts, so you can
get the data at smallish, just not smallest, level and you can do TAZ to Tract
flows"
From: Weinberger Penelope
Sent: Wednesday, October 30, 2013 5:27 PM
To: ctpp-news(a)chrispy.net
Subject: CTPP 5-year data
The CTPP 5-year data, based on ACS 2006 - 2010 Census Data, will be released tomorrow
Thursday, October 31, 2013, the URL to access the data will be published here.
The CTPP Data Access Software is a powerful tool to access the nearly 350 gigs of data
provided by the Census Bureau. The Data set consists of nearly 200 residence based
tables, 115 workplace based tables and 39 flow tables (Home to work) for over 200,000
geographies. The data are derived from two American Community Survey microdata record
sets based on the 2006 - 2010 ACS. One set is the original microdata; all tables derived
from this set are designated A, the other set is a disclosure proofed microdata set; all
tables derived from this set are designated B. That is to say, the first letter in the
table name indicates the set from which the table was derived. For more information on
disclosure proofing, please access the CTPP e-Learning module "Disclosure
Proofing" at:
http://ctpp.training.transportation.org/
The software contains a robust map tool, for both selecting geography and rendering
results. Results can also be presented as various style charts and tables that can be
rearranged to suit your analysis and display needs. Data from the tool can be downloaded
as comma or semi colon delimited .csv, .xml, .shp, .tab.
Some things to be aware of:
This is a new software release and it is possible you may find some errors and bugs as you
use it. Please use the CTPP Feedback form available in the Help menu to report any
problems encountered. (Version 1.1 release, already planned for the near future, reflects
corrections to issues discovered after Beta testing.) Please consider this a Gamma
version.
A PDF tutorial is available in the Help menu and covers much of the software functionality
teaching a sample application. The context sensitive (on-line) help has some bugs that
are currently being addressed. A series of short film tutorials is available on the CTPP
YouTube channel at:
http://www.youtube.com/user/CTPPProgram. The YouTube tutorials
include a software tour, how to register/logon, opening and rearranging a table/accessing
basic data; Geography selection by list and map; Calculating percentages; and Display maps
and thematic analyses. If, after you have exhausted all resources you are still having
trouble please contact pweinberger@aashto.org<mailto:pweinberger@aashto.org> for a
walk through, but please try to find your solution from available resources first.
Training is rolling out both in person and online, we will keep you posted.
Downloads are limited to 100,000 cells. If you need to download large tables they will
need to be split up and stitched back together in excel (or another program). We are
developing a background downloader for large files. In the meantime, if you simply want
all the data for your entire area, send a message to
pweinberger@aashto.org<mailto:pweinberger@aashto.org> and a set with appropriate
documentation will be made available for FTP download. Any very large data set is
unsupported and for power users, comfortable manipulating large data sets in statistical
software packages that they are already licensed to use.
Geographies can be aggregated and margins of error will be correctly re-calculated, but
non-standard (user created) saved geographies cannot be mapped - we are working on this.
Until approximately January 2014, the data set available does not include workplace data
for TAZs with zero (0) populations. This means that any TAZ which consists solely of a
special generator (i.e., an airport, a shopping mall, a business park, the pentagon, etc.)
does not have its associated workplace data or flow to it available. This is being
rectified and a new dataset will be released around January, 2014 that corrects that
problem. Fortunately, the data is available at tract even for zero pop tracts, so you can
get the data at smallish, just not smallest, level and you can do TAZ to Tract flows
Penelope Z. Weinberger
CTPP Program Manager
AASHTO
202-624-3556
ctpp.transportation.org