Dave Mitchell dave.mitchell at NEWGROVE.COM
Wed Aug 24 08:46:06 EDT 2005

Hi List,

I have been investigating the GDAL/OGR with the ODBC connection.

I have been using virtual data files (See the link below)

My understanding is as follows:

1. Non-spatial data

It is possible to plot x,y data from a SQL Server table quite easily as

  <OGRVRTLayer name="mylayer">
  <SrcDataSource>ODBC:mapserver/mapserver at MapServerTest</SrcDataSource>
  <GeometryField encoding="PointFromColumns" x="Easting" y="Northing"/>

2. WKT Spatial Data
If you have an OGC compliant WKT database with a GEOMETRY_COLUMNS table, it
is possible to plot points, Lines, polygons etc.
(It picks up the required columns automatically)

   <OGRVRTLayer name="mylayer3">
   <SrcDataSource>ODBC:mapserver/mapserver at MapServerTest</SrcDataSource>

3. WKB Spatial Data
However the database I am using holds data in the WKB (Well Known Binary)
format and I am not clear whether this is supported by the current OGR
library as the documentations says:

"it is currently a hardcoded assumption that the geometry is in WKT format."
My questions are these:-

1. Have I understood this correctly?
2. Is there a workaround for OGR with a WKB database?
3. Are there any plans to implement this functionality by GDAL/ Mapserver
and if so when?
4. If no, then who might do this custom development for a fee?

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