[mapguide-users] Access DB and coord systems

[Traian Stanev]

Reprojection is done on a stream of data that is independent of the source -- SDF, SHP, Oracle, etc. all pass through the same code for reprojection. That's why it has to be a problem with the way that code gets the coordinate system from the FDO provider (or the provider giving it the wrong coordinate system). 
 
It makes sense that the data still displays because one of the possible fallbacks in that code is to default to identity transform. So your LL data will (incorrectly in this case) display at UTM coordinates close to the UTM origin (between 0 and 180 meters).
 

	-----Original Message----- 
	From: Gord McKenzie [mailto:gord.mckenzie at canam.com] 
	Sent: Wed 8/30/2006 5:33 PM 
	To: users at mapguide.osgeo.org 
	Cc: 
	Subject: RE: [mapguide-users] Access DB and coord systems
	
	

	Not sure if this means much but the data is actually drawn on the map.  If I pan and zoom to the LL coordinates I find my data is there.  So my source data is in LL and my map in UTM.  The weblayout preview shows me that I am zoomed to the extents of my UTM window.  Never the less, the data from my access table is still drawn at it’s LL coordinates.  Going to try this with a SQL Server table and see if that makes any difference.

	 

	I used the getresourcedata function to get an XML output of the Access data source and it would seem to confirm that it knows about LL83 and only LL83.

	 

	Anyone actually successfully transforming LL cords from a DB to something else and if so what database are you using?

	 

	Gord 

	 

	
  _____  


	From: Traian Stanev [mailto:traian.stanev at autodesk.com] 
	Sent: Wednesday, August 30, 2006 1:40 PM
	To: users at mapguide.osgeo.org
	Subject: RE: [mapguide-users] Access DB and coord systems

	 

	 

	One thing I can think of would be if your ODBC connection lists more than one coordinate system when queried by the server and the server then could end up using the wrong one for repro, which would result in the behavior you describe. Another possibility is that it didn't parse the WKT string correctly for the ODBC connection, although that's unlikely, given that LL83 is a popular one.

	 

	Traian

	 

	
  _____  


	From: Gord McKenzie [mailto:gord.mckenzie at canam.com] 
	Sent: Wednesday, August 30, 2006 3:34 PM
	To: users at mapguide.osgeo.org
	Subject: [mapguide-users] Access DB and coord systems

	I have a table in access with lat and long.  I can create and successfully Test Connection to the ODBC database which is identified as LL83.  I can create a layer, a map and a web layout that will show this data.  If I set my map coord system to UTM zone, the data is not transformed.  I can add shape and sdf layers that are LL83 source and reproject just fine.  Only DB data sources don’t seem to want to reproject.

	 

	Can anyone offer any reason or advice?

	 

	Thanks

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/ms-tnef
Size: 8482 bytes
Desc: not available
Url : http://lists.osgeo.org/pipermail/mapguide-users/attachments/20060830/1b77ee8a/attachment.bin