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

[Dylan Oliver]

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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