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

Tue May 3 17:56:18 EDT 2011

Hi Martin,

On 03/05/2011 5:08 PM, Martin Kofahl wrote:
> Hi Assefa,
> you'll find 4326 listed first in line 43 in order to speed up searching some common codes.
>
I missed that.
> 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...
  If the list is correct indeed, I believe that make sense to add the 
mapaxisorder.csv to the bug. I will update the bug on that. I am bit 
hesitant to do the change for 6.0. Could be done for a point release if 
all is confirmed. I will also update the trac bug on this.

Thanks.

>
> 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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-- 
----------------------------------------------------------------
Assefa Yewondwossen
Software Analyst

Email: yassefa at dmsolutions.ca
http://www.dmsolutions.ca/

Phone: (613) 565-5056 (ext 14)
Fax:   (613) 565-0925
----------------------------------------------------------------