The EPSG Contract

Daniel Morissette dmorissette at DMSOLUTIONS.CA
Mon Jan 9 10:10:10 EST 2006

And about WMS 1.3, because of the mess that Paul described below there 
is no plan to support WMS 1.3 in MapServer in the forseeable future (or 
more specifically, I am not planning to do it anytime soon). I think WMS 
1.1.1 is still the most popular out there anyway and might be for a bit.


Paul Ramsey wrote:
> Well, the news from OGC on the WFS/GML issue seems to be to accept  the 
> implemented facts on the ground for older representations of epsg  codes 
> ("EPSG:XXXX") and enforce the "consistent" behavior for newer  
> representations of epsg codes (urn notation).  And the WMS 1.3  
> specification remains as writ, so when Mapserver implements 1.3 it  will 
> need to follow the specification, such as it is.
> This implies, incidentally, some extra infrastructure at the backend,  
> because the current Mapserver source of EPSG CRS information, the  proj4 
> library, does not include ordinate order in its backend epsg  database 
> (the epsg file).  That leaves a pair of unpleasant  implementation 
> paths: add a whole new concept into proj4, and then  have mapserver 
> require the new library version in order to support  WMS 1.3; or do a 
> hack solution and simply assume all +proj=longlat  combinations have 
> reversed ordinates, unfortunately the hack will  omit other cases, like 
> several south african and some european  projects, that also have a 
> northing/easting order.
> So long story long: no news :)
> P
> On Jan 7, 2006, at 8:30 AM, Arnulf Christl wrote:
>> Any news here? Sorry if i missed it. We want to support 1.3 and are  
>> trying to get an overview of which services will support it in  which 
>> way. We are the poor last layer and have to deal with  whatever you 
>> spit at us.
>> Best, Arnulf
>> Paul Ramsey wrote:
>>> I have also tried the Intergraph WFS and it is in easting/ northing, so
>>> that makes 3 so far:
>>>   Mapserver
>>>   Cubewerx
>>>   Intergraph
>>> Will be interesting to hear what the wfs list says.
>>> Frank Warmerdam wrote:
>>>> On 5/19/05, Paul Ramsey <pramsey at> wrote:
>>>>> Is it so bad to suck it up and follow the standards consensus,  no 
>>>>> matter
>>>>> how silly? Sometimes bad decisions are made, but walking away  from 
>>>>> the
>>>>> process destroys all the good decisions too.
>>>> Paul,
>>>> I do see your point, and I have certainly accepted that when  MapServer
>>>> implements WMS 1.3 it will have to address this issue properly.   
>>>> However,
>>>> the WFS stuff has existed for quite a while (as has GML) but this  
>>>> issue
>>>> is only being raised now in the WFS/GML context.  So we are left
>>>> having to back-fix without any obvious indicate of what is really  
>>>> the right
>>>> thing to do.
>>>> I *suspect* that at least for GML 2 the coordinate system does not
>>>> control order of values in coordinate tuples.  I'm sure I have heard
>>>> previous detailed discussios to this effect.  I am not at all  sure of
>>>> the situation with GML3.
>>>> Hopefully we can isolate these issues to GML3 and WMS 1.3+ so that
>>>> a simple version check will suffice to make the decision clear.
>>>> Best regards,

  Daniel Morissette               dmorissette at
  DM Solutions Group    

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