[Gdal-dev] OGR: TIGER/Line polygons

[Schuyler Erle]

* On 20-Oct-2004 at  2:33PM PDT, Curt, WE7U said:
> 
> I end up with a LOT of polygons.  Upon drawing that shapefile
> polygon file to my display it looks very similar to what it would
> look like if I had drawn all of the individual line features from
> multiple layers of the original raw tiger file. 

Yes, that is what you get - TIGER/Line, frankly, contains a lot of
polygons! If you do a topological cleanup - removing spurs and bridges
and so on - you get the actual polygons, one per census block - which
is typically a pretty small area.  Like I said earlier, I use GRASS
for this.

> So far I'm no closer to getting a Shapefile with just the lake
> polygons in it.  I'll keep studying the TIGER docs and the Python
> script and will learn more about it.

The one thing tigerpoly.py doesn't do is connect area landmarks with
the polygons - I've been pondering how to do this. However, if hydro
features are all you're after, you can try selecting and merging the
polygons from TIGER/Line that have a ZCTA5 attribute ending in 'HH' -
this seems to select all of the water polygons in my vector layers.

SDE