[postgis-users] TIGER polygons, census SF1 blocks, and boundaries

[phat-ass at thinkheavyindustries.com]

I think you are going to have to import the completechain information
too.

Read Blasby's instructions on how to load Tiger basedata. I had some
problems with his instructions and had to work out a slightly different
scheme. If his instructions don't work I think I can walk you through
what I did. You're only using one county right now, though, I gather, so
it shouldn't be difficult.

With that data, you don't even need the polygon data, actually, unless
you are trying to draw the data with qgis or something.

Have you read the Tiger/Line documentation from census.gov?

You need to make a link between the completechain data to the polygon
data if you need the polygon data. It's a pain, I know, but the POLYID
field is, dynamic, and changes from one Tiger revision to the next. 

There is an easier way of going about this, I think. 

But to start, you need to load the completechain data and go from there.

This may actually be a lot easier than what I'm looking at.

What are you trying to do? Are you trying to determine number of houses
covered by antennae coverage block by block? And with that I would
assume you are trying to gather relative signal strength vs distance
from some tower or other RF source? Or some such...

You may not even need the polygon data at all. The complete chain may
very well be all you need.

phat



On Wed, 2006-03-22 at 22:53 -0600, Dylan Oliver wrote:
> what up phat,
> 
> I'd be happy to help you however I can with this TIGER/census/postgis
> thing. It's not the polished process that it should be!
> 
> I'm using plain ogr2ogr to import the TIGER data. I've been using
> tigerpolytransformation by David Blasby as described in the GeoServer
> docs (though I'm not using GeoServer). Of course, this program only
> works on the polygons which have already been imported through
> ogr2ogr. 
> 
> Every time I end up with several records containing the same module,
> tract, and block but with different polyids and geometries. I assume
> that these are bodies of water or parks or other features within the
> blocks, so it makes sense that there should be multiple polygons per
> block. Only one should represent the outline of the block, but I've
> found no fields to discern these: 
> 
> (roughly)
> 
> select module, tract, block, polyid where module='tgr55111' and
> tract=43 and block=1034;
> 
> module  tract  block  polyid
> tgr55111  43  1034  53
> tgr55111  43  1034  54
> tgr55111  43  1034  55 
> 
> So which one is the block border and not a lake or something? Note
> that I'm not including the many other fields in the polygon table, as
> they are all the same for these polygons sharing a block. They have
> different geometries, and I've thought of selecting the one with the
> biggest area or the like. But this seems really stupid, and there
> should just be a binary isblockborder or something similarly obvious. 
> 
> This is after I import the data with ogr2ogr, and before I do anything
> else!
> 
> I'm not actually using a geocoder at the moment. I'm importing a file
> of RF coverage data which consists of coordinates and predicted signal
> levels. This is all A-OK and interesting, but not really relevant to
> the border issue! 
> 
> Best,
> -- 
> Dylan Oliver
> Primaverity, LLC 
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