[ms4w-users] OGR VRT datasource with SrcSQL clause resulting in empty layer

Frank Warmerdam warmerdam at pobox.com
Thu Sep 7 12:18:19 EDT 2006


Andre van Atten wrote:
> A sample of what I would like to be working correctly is the use of
> wkbLineString instead of wkbPoint: (Draw a layer directly from a
> database view, with lines between two points, where the LINESTRING field
> is for example: 
> LINESTRING (X1 Y1 , X2 Y2)
> 
> <OGRVRTDataSource>
>         <OGRVRTLayer name="LayerTopologyLINESTRING">
>         <SrcDataSource>ODBC:@Datacsourcename</SrcDataSource>
>         <SrcLayer>LayerTopologyLINESTRING</SrcLayer>
>         <GeometryField encoding="WKB" field="LINESTRING"/>
>         <GeometryType>wkbLineString</GeometryType>
>         </OGRVRTLayer>
> </OGRVRTDataSource>
> 
> So it seems the wkb-functionality is not always linked with all it's
> rich functionality into MapServer. OGRINFO displays correct results then
> however, but OGRINFO is not MapServer.
> Because I am a typical user and not a developper I am not able to
> pinpoint the problem in the code.  

Andre,

I can't think of any obvious reason that WKB encoding for linestrings would
work through ogrinfo but not through mapserver if other VRT/ODBC stuff is
working ok for mapserver.

Best regards,--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org



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