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Wed, 15 Mar 1995 20:01:00 EST |
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----------------------------Original message----------------------------
<start>
The "Archive of Census Related Products", located at
ftp ftp.ciesin.org
cd /pub/census
contains a few improvements ...
o Based on user requests, we have created thinned COUNTY and STATE files
for the CONTIGUOUS US. These thinned files are a simple concatenation of
the county files for the 49 contiguous USA states. Thinning the files
has been done in 3 steps, reducing polygon points by 50% in each step.
These "thinning levels" are indicated by the "thx" filename, where x gets
assigned a value 1,2 or 3, indicating increasing thinning levels. (The
filename designation "00" indicates US contiguous area, instead of FIPS
codes).
/pub/census/usa/tiger/us/original
c00.zip unthinned county file
s00.zip unthinned state file
/pub/census/usa/tiger/us/thinned
c00th1.zip thinned county file
c00th2.zip thinned county file
c00th3.zip thinned county file
o 1% and 5% PUMAS (Public Use Microdata Sample Areas) COVERAGES.
Based on a new equivalency file obtained from the Bureau of the
Census ("pumgef"), we have regenerated the PUMA boundary files,
This new file yields much better coverages, although problems remain,
dramatically reducing the number of unchainable polygons.
The coverages for 1% PUMS (bpuma) and 5% PUMS (apuma) are posted in
unthinned and thinned formats. In addition we provide a file with
geographic centroids for the PUMS coverages (based on UIC's genlabs
macro).
/pub/census/usa/tiger/us/original
ap00.zip unthinned apumas
ap00ctrd.zip unthinned apuma centroids
apumas.not apuma failure report
bp00.zip unthinned bpumas
bp00ctrd.zip unthinned bpuma centroids
bpumas.not bpuma failure report
/pub/census/usa/tiger/us/thinned
ap00th1.zip thinned apuma file
ap00th2.zip thinned apuma file
bp00th1.zip thinned bpuma file
bp00th2.zip thinned bpuma file
ap00th1.txt apuma flushing report
ap00th2.txt apuma flushing report
bp00th1.txt bpuma flushing report
bp00th2.txt bpuma flushing report
NOTE: The "[a/b]pumas.not" files indicate the problem areas we
encountered. There are basically 2 main areas: LA County, CA (yet, again)
and Baltimore County, MD. In addition PUMAS infrequently fail in the New
England states. We are very interested to hear from local experts
in the area on thoughts of fixing these errors (even a manual fix
appears very doable -- please email [log in to unmask] or
[log in to unmask] directly).
NOTE2: When thinning, especially severely, "slivers" and areas of less
than 3 points may develop. These PUMAS are flushed when writing the BNA
files,please check the "[a/b]p00th[1/2/3].txt reports.
<end>
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