[Mapserver-users] Projections

[Ed McNierney]

John -

The PROJECTION object at the top-level in your MAP file describes the desired projection of the output image.  The PROJECTION object inside each LAYER object describes the source projection of the data for that layer.  That's the only way MapServer knows whether the source data needs to be (re)projected when it's added to the output image.

If your data is in geographic coordinates, you need to have a PROJECTION block such as:

 	Projection
		proj=latlong
		ellps=GRS80
	End

(assuming that's the correct ellipsoid) in the LAYER block.  Otherwise MapServer will assume that the input is the same as the output projection and do nothing to project it.

There may also be an image size problem, but let's fix this one first!

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 

-----Original Message-----
From: John McCue [mailto:jmccue at geovue.com]
Sent: Tuesday, January 14, 2003 12:22 PM
To: Mapserver-Users
Subject: [Mapserver-users] Projections


I am still trying to get a correct projection in MapServer.  I have defined
a PROJECTION object in the MAP object to use an EPSG code:
PROJECTION
  "init=epsg:26986"  #Massachusetts Mainland State Plane, NAD83
END

I have also defined that same projection in each of my layers. My data is in
geographic coordinates (lon/lat).

My problem is that the image appears to be contracted from north to south.

	- Are my projection specifications correct?

	- Is this a different problem, maybe setting the image size?

Thanks for any help,
John



_______________________________________________
Mapserver-users mailing list
Mapserver-users at lists.gis.umn.edu
http://lists.gis.umn.edu/mailman/listinfo/mapserver-users