[mapserver-dev] Axis order in WMS 1.3.0 (#3582)

[Martin Kofahl]

Hi Assefa,
you'll find 4326 listed first in line 43 in order to speed up searching some common codes.

I'm not 100% sure about this list, it's generated from the epsg database and there are the axes orientations defined. WMS spec tell's us to care about the axis order. Regarding epsg:31468 and epsg:4326 (the ones I usually use) sql output is correct. After applying the patch people could use the WMS with ArcGIS. In case the list is correct, waiting for user contributions could take a while. 

I'll read through the specs agaian...
 
Martin

-------- Original-Nachricht --------
> Datum: Tue, 03 May 2011 16:38:45 -0400
> Von: Yewondwossen Assefa <yassefa at dmsolutions.ca>
> An: mapserver-dev at lists.osgeo.org
> Betreff: Re: [mapserver-dev] Axis order in WMS 1.3.0 (#3582)

> On 03/05/2011 3:34 PM, Martin Kofahl wrote:
> > Hi,
> >
> > in my mind MapServer still doesn't handle the axis order correctly for
> WMS 1.3.0 requests. The current implementation does first check a static
> list of epsg codes about axis orientation and otherwisely swap axes for epsg
> 4000-4999. (See http://trac.osgeo.org/mapserver/changeset/11155#file4,
> http://trac.osgeo.org/mapserver/browser/trunk/mapserver/mapaxisorder.csv?rev=11155)
> >
> > Epsg codes with swapped axes commonly used in Germany are currently
> neglected and there are probably many more. As more and more WMS 1.3.0 clients
> come up, users get confused about WMS suddenly deliver a blank map (because
> of misinterpreted bbox).
> >
> > MapServer makes the one who compiles MapServer responsible for the
> swapped-axis-codelist (mapaxisorder.csv). That's why I worry that there will be
> different MapServer 6 versions running with different handling of the axes
> order for identical requests.
> >
>   I think this last paragraph is somehow incorrect, MapServer uses 
> mapaxisorder.h to compile.  mapaxisorder.csv and the script 
> mapaxisorder.sh are mechanism to generate mapaxisorder.h. This file is 
> committed. So if someone compiles out of the box, there is no reason to 
> think that he would get a different result.
> The mechanism is there so that it is easy for people to generate 
> mapaxisorder.h instead of editing it by hand. If they want, they can 
> then contribute back their epsg codes and we will generate a new 
> mapaxisorder.h and commit so others would have them.
> The initial list that I put there is based on the epsg listed in the bug 
> as being "inversed" coordinates but not working currently with the logic 
> of assuming that all espg codes between 4000-5000 are "inversed".
> > The best would be to make MapServer axes-orientation-aware. Using the
> sql snippet from http://trac.osgeo.org/mapserver/ticket/3582#comment:13 I got
> about 1700 epsg codes with north/east (resp. south/west) axes, see
> http://trac.osgeo.org/mapserver/attachment/ticket/3582/mapaxisorder.h. I'm no
> expert in foreign epsg codes. From my understanding they all should be marked
> having swapped axes when processing WMS 1.3.0 requests. Someone who con
> confirm this? What about implementing the whole list into MapServer ... and
> hoping the best?
> >
>   I am not sure what is the best way to know all the epsg code that are 
> inversed. I was more under the impression that this list in 
> mapaxisorder.h would be more of an  an exception list than a long list 
> of >1000 elements. Are you sure about this list provided in the bug? I  
> am also a bit suspicious about it since I do not see 4326 which I know 
> should be inverted.
> 
> best regards,
> 
> > Best regards,
> > Martin
> > _______________________________________________
> > mapserver-dev mailing list
> > mapserver-dev at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapserver-dev
> >
> 
> 
> -- 
> ----------------------------------------------------------------
> Assefa Yewondwossen
> Software Analyst
> 
> Email: yassefa at dmsolutions.ca
> http://www.dmsolutions.ca/
> 
> Phone: (613) 565-5056 (ext 14)
> Fax:   (613) 565-0925
> ----------------------------------------------------------------
> 
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