[postgis-users] TIGER/Line Shapefiles released

[Stephen Woodbridge]

Stephen Frost wrote:
> Jonathan,
> 
> * Jonathan W. Lowe (jlowe at giswebsite.com) 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 (sfrost at snowman.net) 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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