proj=eqc with change of latitute

[Ed McNierney]

Espen -

Those EXTENT values look odd.  Your projection's X-origin is still at 0 degrees longitude.  If your X coordinates are 10 degrees East, then the projected coordinates (in meters) shouldn't be about 37,000.  That would mean you're about 37 km east of the prime meridian, and you're not.  At 60 degrees North latitude one degree of longitude is 55.8 km, so if you're 10 degrees East you should have an X coordinate of about 558,000 meters (a little more, since you're more than 10 degrees East).

When I use PROJ or CS2CS to project your values I get exactly the same Y values but very different X values:

cs2cs +from +init=epsg:4326 +to +proj=eqc +lat_ts=60 +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +no_defs +units=m
10.6661 59.9155
593672.41       6669762.95 0.00
10.6824 59.9213
594579.66       6670408.60 0.00

These X values seem reasonable for your projection.  The command line you give for PROJ shouldn't actually work as given - the quotes get in the way.  You should be using a command like the one above to CS2CS, or:

proj +proj=eqc +lat_ts=60 +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +no_defs +units=m

for the conversion.  I'm a little puzzled as to how you're getting those results.  Could you try both the PROJ and CS2CS command lines above to double-check, and report the version of PROJ you're using?  There's probably something obvious here but I'm not seeing it.

     - Ed

Ed McNierney
Chief Mapmaker
Demand Media / TopoZone.com
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
Phone: +1 (978) 251-4242
Fax: +1 (978) 251-1396

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of Espen Isaksen
Sent: Tuesday, January 22, 2008 1:45 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: [UMN_MAPSERVER-USERS] proj=eqc with change of latitute

Hi!

This question originates from this earlier thread:

http://lists.umn.edu/cgi-bin/wa?A2=ind0801&L=mapserver-users&D=1&T=0&P=37923

But since I learned a lot during that thread and because the thread is
full of all kinds of questions now I would like to ask a very specific
question again in a new thread.

I have also checked out the archives at this list and the PROJ list. I
have found one similar question on this list in 2005:

http://lists.umn.edu/cgi-bin/wa?A2=ind0504&L=MAPSERVER-USERS&P=R75005

Here is my question:

I have set up a mapfile with projection parameters like this:

EXTENT 10.6661 59.9155 10.6824 59.9213
PROJECTION
    "init:epsg:4326"
END