[Mapserver-users] projection issues

[Jeff Hoffmann]

Leah Roderman wrote:

> I always tangle with projection issues and then forget my solutions.
> 
> Problem: My coordinates are misaligned with my TIGER shapefiles.
> 
> The long explanation: I am using TIGER '90 polygons and line features.
> Atop these, I am displaying points used by taking GPS readings, saving
> them in Postgres, and retrieving them via PostGIS.

> I am collecting GPS data using a Garmin etrex Vista. The export file I
> generate for coordinates includes "Datum   WGS 84" at top. My
> understanding of TIGER is that it is not in any projection (based on
> http://www.census.gov/geo/www/tlmetadata/metadata.html).

I use EPSG 4269 for newer TIGER which seems to work fine.  I haven't 
used older TIGER, but since they say they use NAD27 pre-1994, I'd guess 
you'd want to use EPSG 4267.  I don't know about the GPS coordinates, 
although I would start by trying EPSG 4326.

-- 

Jeff Hoffmann
PropertyKey.com