[mapguide-users] WMS Consumption and Coordinate Transformation

[Andy Morsell]

For those researching the same issue, I have created a Wiki page that should
help you with this.  Jason suggested the potential of using a resource
config document and Autodesk supplied an internal document that describes
this process.  I essentially copied this document to the Wiki page, so it is
now available to everyone to use.  The process is a little arduous and prone
to mistake in the case of typos or syntax errors, but I can attest that it
works at least in the case of using a different EPSG coordinate system for
your WMS requests.  Further, I understand that the MGOS development team
would like to implement an easier method for applying these config documents
and possibly expose some of the override options directly in MapGuide Studio
when configuring a pertinent resource.
 
The page can be found here:
 
https://trac.osgeo.org/fdo/wiki/FdoWmsNotes
 

Andy Morsell, P.E. 
Spatial Integrators, Inc. 
http://www.SpatialGIS.com 

  _____  

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Andy Morsell
Sent: Tuesday, February 12, 2008 11:52 AM
To: 'MapGuide Users Mail List'
Subject: [mapguide-users] WMS Consumption and Coordinate Transformation



I am trying to straighten this out since I am fairly confused about MapGuide
and WMS coordinate transformations.  There have been many discussions in the
past about this, some of which I've been part of, but most pertain to the
SERVING of WMS layers rather than consuming them.

In this case, I need to consume a WMS layer published in EPSG:4326 and have
it displayed in a MGOS or MGE map using EPSG 2914.  In Studio, the
datasource works fine, and the layer displays fine using 4326.  In turn, a
4326 map displays the layer fine, but a map in any other coordinate system
will not display the WMS layer data.

Exactly how does how this happen on the back-end of MGOS since one cannot
specify a coordinate system for a WMS datasource?  Is it supposed  to look
up the EPSG code from the maps assigned coordinate system code and then
incorporate that (and the bounding box info) into the WMS request?  Is there
any way to find out what WMS requests are actually being formed for
trouble-shooting purposes?  

I know that the EPSG code exists on the server as I am able to use the
ConvertEpsgCodetoWkt via the mapagent.  The server in question is an ER
Mapper server and I saw a reference to MGOS URL encoding the WMS requests
and that this is supposed to be fixed in R2.  However, I tested with version
2 RC2 and see the same problems.

Issuing the WMS requests within a browser (or via Gaia) works just fine with
different EPSG codes. 

 
<http://wms.oregonexplorer.info/ImageX/ecw_wms.dll?REQUEST=GetMap&SERVICE=WM
S&VERSION=1.1.1&LAYERS=2005ORTHOIMAGERY.ECW&STYLES=&FORMAT=image/png&BGCOLOR
=0xFFFFFF&TRANSPARENT=TRUE&SRS=EPSG:4326&BBOX=-124.5666667,40.6839378963289,
-116.428612945493,47.5664062144262&WIDTH=875&HEIGHT=740>
http://wms.oregonexplorer.info/ImageX/ecw_wms.dll?REQUEST=GetMap&SERVICE=WMS
&VERSION=1.1.1&LAYERS=2005ORTHOIMAGERY.ECW&STYLES=&FORMAT=image/png&BGCOLOR=
0xFFFFFF&TRANSPARENT=TRUE&SRS=EPSG:4326&BBOX=-124.5666667,40.6839378963289,-
116.428612945493,47.5664062144262&WIDTH=875&HEIGHT=740

 
<http://wms.oregonexplorer.info/ImageX/ecw_wms.dll?REQUEST=GetMap&SERVICE=WM
S&VERSION=1.1.1&LAYERS=2005ORTHOIMAGERY.ECW&STYLES=&FORMAT=image/png&BGCOLOR
=0xFFFFFF&TRANSPARENT=TRUE&SRS=EPSG:2914&BBOX=3814657.887703,-27439.92951706
87,6029145.271766,1845383.68671907&WIDTH=875&HEIGHT=740>
http://wms.oregonexplorer.info/ImageX/ecw_wms.dll?REQUEST=GetMap&SERVICE=WMS
&VERSION=1.1.1&LAYERS=2005ORTHOIMAGERY.ECW&STYLES=&FORMAT=image/png&BGCOLOR=
0xFFFFFF&TRANSPARENT=TRUE&SRS=EPSG:2914&BBOX=3814657.887703,-27439.929517068
7,6029145.271766,1845383.68671907&WIDTH=875&HEIGHT=740

Any help or explainations would be appreciated.  Thank you very much. 

Andy Morsell, P.E. 
Spatial Integrators, Inc. 
 <http://www.SpatialGIS.com> http://www.SpatialGIS.com 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/mapguide-users/attachments/20080215/12b0a7a0/attachment.html