You need to do your analysis in a projected coordinate system, not geographics.
CREATE TABLE my_new_texas_roads AS
SELECT ST_Transform(the_geom, 3081) as the_geom, other_attributes
FROM texas_roads;
EPSG:3081 should be a good coordinate system for working with your Texas data.
http://spatialref
I am trying to determine mile markers along Texas highways. My starting
point is the ShapeFile TxDOT Roadways 2010 at
http://www.tnris.state.tx.us/datadownload/download.jsp. I've used shp2pgsql
to get it into a PostGIS 1.52-enabled Postgres 9.01 database.
I naively thought I could just figure out
