[mapserver-dev] PROJ4 and EPSG database

[Yewondwossen Assefa]

Frank Warmerdam wrote:
> Yewondwossen Assefa wrote:
>> Frank Warmerdam wrote:
>>>
>>> Folks,
>>>
>>> I would point out that MapServer already has a concept of axis ordering
>>> implemented for WCS.  Of note are the msAxisNormalizePoints() and
>>> msAxisDenormalizePoints() functions in mapproject.c.  These are tied to
>>> epsgaxis= settings which can be "en" for easting,northing or "ne" for
>>> northing,easting.
>>>
>>> Currently mapfile.c's proj init function has a special case to set this
>>> parameter for EPSG urn's in a particular range.  In the short term I
>>> think this is the logical mechanism to extend when working on WMS 1.3.0.
>>>
>>
>> Frank,
>>
>> This is exactly how I am implementing the proj support for wms1.3.0: 
>> extend the functions to support more CRS codes and the AUTO2.  The 
>> only difference that I saw from WCS1.1 would be to allow all EPSG 
>> projection strings (given as Urns or just ESPG:XXXX) to pass though 
>> the functions to set the axes order for those particular ESPG ranges.
> 
> Assefa,
> 
> I do not think we can have EPSG:4326 be assumed to be lat/long for all
> services, so some mechanism will need to be put in place to alter the
> behavior in WMS 1.3 mode.  Possibly you could alter EPSG: to EPSGA: in
> the WMS 1.3 handler code and we could look for that.   Or even replace
> the EPSG: with the corresponding URN before calling the
> msLoadProjectionString() function.  What I don't want is for the axis
> stuff to be altered when folks have EPSG: metadata set or with WMS 1.1.
> 
> Best regards,
> 

Frank,

I made sure that I did not modify the behavior for other services 
regarding msLoadProjectionString and the ESPG.  What I have implemented 
for now (not committed yet) is that WMS 1.3.0 uses a function that only 
checks the ESPG:XXX syntax (and does the axes orientations settings). If 
the string is not of the ESPG:XXX type, It goes to msLoadProjectionString.
 From the tests I have done, nothing has changed for WMS 1.1.1 for 
example.

Best Regards,



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

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

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