Stephen Frost wrote:
Jonathan,
* Jonathan W. Lowe ([EMAIL PROTECTED]) wrote:
Have you yet tried overlaying TIGER 2007 linework or census block/tract
polygons over Google or OpenStreetMap tiles? I'm seeing a good match in
some areas but a significant shift (~50 meters) in others. Thought it
might be a datum conversion issue, but can't seem to find a match.
I hadn't looked at the linework too much yet or tried to overlay it.
I'm curious where you're seeing the differences though because I know
that Census is only about half way through their MAF improvment project
and I actually have some info about what has been done so far and what
hasn't. It'd be interesting to see if it matches up.
There are a few places (Guam, Hawaii islands) where they actually do use
an SRID other than 4269, but my scripts don't yet handle that and I'm
guessing that's not what you're referring to anyway. :)
I had an extensive discussion with some of the Census Geography staff
about the Island provinces and Hawaii because I was trying to align
Navteq routes over Tiger data and the Navteq routes were about a .25-.5
miles east of the Tiger data in Hawaii.
It turns out that they really have not idea what the "local datums" are
that were originally used. I tried a lot of the local Island datums in
the proj4 epsg file but could not find any close matches.
It will be nice when they get that fixed up :)
Stephen - thank you for sharing your scripts.
Best regards,
-Stephen Woodbridge
http://imaptools.com/
Thanks!
Stephen
On Thu, 2008-04-03 at 17:07 -0400, Stephen Frost wrote:
* Stephen Frost ([EMAIL PROTECTED]) wrote:
I think they may have also upgraded their pipe.. I got about 1.41MB/s
(11 Mb/s) for the whole transfer. It's about 22G all told. I'll
probably be trying to load it up into PG on one of our servers tomorrow.
It was a bit over 4 hours for me to pull down off of their
ftp2.census.gov ftp site.
Just to update those who might be interested- I've finished the data
load into one of our servers at work. It comes to ~60GB on disk in
PostgreSQL/PostGIS with appropriate indexes in most places and whatnot.
Based on what I've seen so far, it looks *very* nice, especially the
hydrogrophy ("areawater"). It also appears to be pretty consistant
across the layers, which is also good.
If anyone's interested in the scripts used to load the data (they're
pretty simple, really), I'd be happy to provide them.
Enjoy,
Stephen
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