Hi again! This is what I try to do. I understand that I am now using a projected coordinate system with 60N as my latitude of true scale.
First I create a mapfile using EPSG:4326 and output a map of a smaller area from this mapfile. Then I take the same extent as as I use in my geographic mapfile and put those coordinates in a textfile. Then I use the following command to transform these coordinates to my new projected coordinate system: proj +proj=eqc +lat_ts=60 +lon_0=0 +x_0=0 +y_0=0 + ellips=WGS84 +datum=WGS84 +no_defs +units=m < test.txt I get my new coordinates as my output. I then create a mapfile, now using the projected coordinate system instead of EPSG:4326 and using my new coordinates for my extent. Creating an output map for this mapfile creates a map from a very different area than my former mapfile using 4326. Doing the same, just converting to UTM32 instead creates a map of the same area as 4326 does. This leads me to believe that I am doing the right thing with my mapfile. Espen On 18/01/2008, Ed McNierney <[EMAIL PROTECTED]> wrote: > Espen - > > I don't quite understand what you mean when you say "proj cannot transform my > coordinates". Could you explain exactly what it is you're trying to do, and > what you think PROJ is or is not doing? > > Please keep in mind that you have moved from a geographic coordinate system > to a projected coordinate system, and that that is a material and substantial > change. It's not simply a matter of "shifting the latitude" but of actually > projecting your data to an equirectangular projection with 60N as the > latitude of true scale. PROJ can certainly also transform coordinates in > that projection back to a geographic coordinate system, but that's a separate > task. You're asking MapServer to create a projected output map, and that > output map's coordinate system will, of necessity, be the projected > coordinate system. > > If you also need to display coordinates in a different coordinate system > (such as latitude/longitude) then that is an additional task that you will > need to do separate from the projection of your map image. > > - Ed > > Ed McNierney > Chief Mapmaker > Demand Media / TopoZone.com > 73 Princeton Street, Suite 305 > North Chelmsford, MA 01863 > [EMAIL PROTECTED] > Phone: +1 (978) 251-4242 > Fax: +1 (978) 251-1396 >
