TIGER/Line processing

Question

Does anyone know of scripts for merging TIGER/Line shp files? It is for extracting the road features only, but for the whole of USA.

They are provided as shp files for one county at a time here: http://www.census.gov/geo/www/tiger/

If anyone sells the data, a link is also appreciated.

Answer 1

There are tools for uploading tiger data to PostGIS. It might be a little easier to work with once it's in PostGIS. Here are some links:

http://pylab.blogspot.com/2007/02/import-tiger-database-to-postgis.html http://geoserver.org/display/GEOSDOC/Loading+TIGER+polygons+tigerpoly.pl

Here's a ruby script for parsing Tiger data:

http://wiki.openstreetmap.org/wiki/TIGER

Edit:

So, you want a shape file for all the roads in the U.S. I believe that would be a fairly large shp file. Does it have to be from Tiger? You can get the major highways in the U.S. from here.

It looks like MapWindow should allow you to merge shp files. I believe QuantumGIS does also.

Finally, here is a free tool whose only purpose is to merge shp files. This looks perfect for what you want.

Answer 2

The ogr2ogr utility of OGR will do the trick, here's an example adapted from the FAQ:

# loop through all of the shapefiles in the directory and load them
for i in $(ls *.shp); do
  ogr2ogr -f 'ESRI Shapefile' -a_srs "EPSG:4269" -nln merged_tiger_roads $i -update -append -skipfailures
done 

This should produce a single merged_tiger_roads.shp from the collection of shapefiles. The FAQ has additional examples of batch merging if you need a more complex workflow.