I'm responding to you and the CTPP-News listserv, since these effect
many different folks. My hopes are that the Census Bureau or USDOT
staff can corroborate or correct me as needed.
1. The TIGER files *can't* be corrected as part of this WORK-UP
project. So, if the TIGER/ArcView files are missing key streets, or
address ranges on streets, then I think the best solution is to code
to the closest available block-face. The idea is to get the
employer location accurately coded to the nearest census block.
Once the Census Bureau is able to geocode to the nearest block, then
they will be able to aggregate to the CTPP Travel Analysis Zones
created as part of TAZ-UP.
If, on the other hand, the employer is within a large new subdivision
that *isn't* included in the current set of TIGER/ArcView files, then
I don't know what happens. I haven't come across this problem, though
I have had problems with streets-without-address ranges.
2. The alias street name problem is one I've been battling with as
early as this morning. The TIGER file will probably have the older
name (e.g., North Main Street), but the "newcomers" to the area may
be used to the new street name (e.g., Last Chance Gulch). [This is
very common in the City of San Francisco where they rename streets
after famous labor leaders or writers, e.g., Army Street is now
Cesar Chavez Street, Ivy Street is now Lech Walesa St., Stark
St. is now Jack Kerouac Alley, etc.] In answering Census 2000,
respondents will use what they want (North Main or Last Chance
Gulch). Maybe the Census Bureau Geography Division has a "street name
alias file" that can be used for improved workplace coding???? (If
not, they should!)
My recommendation may be to add duplicate employer records that have
the alias street name, e.g., if the employer record provided by the
Census Bureau is Joe's Bar & Grill, 100 North Main Street, then I
would add a new record (at the same precise geocoded location) as:
Joe's Bar & Grill, 100 Last Chance Gulch. (Now, if there were 500
establishments along this Last Chance Gulch, then I'd have second
thoughts about adding alias employer records.)
I've been working on WORK-UP for the past week, and I've completed
initial work on five of my nine counties. In the Bay Area we have 300
thousand geocoded employer locations, and 32,800 un-geocoded employer
locations. Of the 32,800 ungeocoded, 1,102 are for employers of 50+
employees. In my large counties, I'm only reviewing the ungeocoded
for the 50+ employees (10+ employees in Napa County). The goal in my
initial work is to "eliminate the big red dots" (ungeocoded
workplaces of 50+).
I'm also reviewing *all* of the geocoded records for large (250+ or
500+) employers to make sure they're in the right locations. They
mostly are, though there were some problems (UCBerkeley was located
in downtown Berkeley instead of on the campus; Marine World USA
amusement park was on the wrong side of the road....) And some of
the research is actually kind of fun (finding the correct location
for Domaine Chandon & Niebaum-Coppola wineries; "Skywalker Sound" in
Marin County....) Unfortunately, a lot of the ungeocoded records are
shopping centers (they're a real mess.)
So, my first phase strategy is to correct the ungeocoded large
employers (10+ or 50+ employees); and to review the existing
geocoding for very large employers (250+ or 500+). I haven't yet
devised a second phase strategy.
3. My question: would it be useful to include the acronym of the
employer in the employer name alias fielf? For example, I doubt that
our friends at AASHTO will fill in American Association of State
Highway Transportation Officials, but rather just use AASHTO....
Chuck Purvis, MTC
Hi Chuck, We are working on the Work-Up assignment.
We have run
into a number of problems that we need guidance with. One problem
is that we are finding road segments in the tiger line files that
do not have a to and from address or zip code coded into them,
thus they are unable to be located. Another problem is that some
of the addresses are on streets that are not in the tiger line
files as a segment. And a third problem is that some of the
streets actually have two (2) different names, i.e. some people
think they are N Main and others think it is Last Chance Gulch.
What makes some of these problems persistent is that the ArcView
file does not allow for editing. The buttons are turned off or
greyed out/invisible. What is the silver bullet strategy that we
need to follow on this assignment. Thank you.
Chuck Purvis, AICP
Senior Transportation Planner/Analyst, Planning Section
Metropolitan Transportation Commission
101 Eighth Street, Oakland, CA 94607-4700
(510) 464-7731 (voice) (510) 464-7848 (fax)
MTC DataMart: http://www.mtc.ca.gov/datamart/
MTC FTP Site: ftp://ftp.abag.ca.gov/pub/mtc/planning/