[Mapserver-users] WMS BBOX vs. Actual Bounds

[Ed McNierney]

Ian -

How is it possible to honor all parameters when they are not consistent?
I certainly understand the need to deal with unusual output devices as
you describe, but it is not very difficult for the client to address
that situation.

	- Ed


Ed McNierney
President and Chief Mapmaker
TopoZone.com
ed at topozone.com


-----Original Message-----
From: Ian Turton [mailto:ian at geography.leeds.ac.uk] 
Sent: Thursday, January 08, 2004 9:10 AM
To: Ed McNierney; Ian Turton; Steve Lime;
mapserver-users at lists.gis.umn.edu
Subject: RE: [Mapserver-users] WMS BBOX vs. Actual Bounds

At 08:56 08/01/2004 -0500, Ed McNierney wrote:
>Ian -
>
>I can't agree that this is poor behavior.  MapServer should also be 
>expected to return a map in the PROJECTION requested, which is 
>impossible under your scheme.  In WMS mode the SRS is part of the 
>request and should be respected just as much as the WIDTH, HEIGHT, and 
>BBOX parameters, shouldn't it?

Indeed - they are all important. However the WMS spec is very specific
about how to handle this case and it says you must honour all the
parameters. Otherwise people like the origianl poster are left not
knowing what they got back.

>If you want the image "distorted", you're not looking for a map - 
>you're making a picture.  If you can define the distortion in a 
>cartographically accurate way (e.g. a picture), then it is indeed a 
>map; but you can also provide MapServer with the definition of that 
>projection and cause it to "distort" the image the way you want.

For example, suppose I'm displaying my picture/map on a display with non
square pixels?

Ian

Ian Turton, Director, Centre for Computational Geography, University of
Leeds, Leeds, LS2 9JT http://www.geog.leeds.ac.uk/people/i.turton
http://www.ccg.leeds.ac.uk http://www.geotools.org
+44 (0) 113 343 3392 fax: +44 (0) 113 343 3308