Dear all,
Mapnik newbie here. After a few headaches, I've managed to compile Mapnik and its dependencies to run under Windows, and I can successfully run the rundemo.py script to create a beautiful map. :) However, I'm a bit stuck at the next step. My source data is held in SQL Server 2008 - in separate tables for polygon, polyline, and point layers, stored using the geometry datatype. I didn't expect Mapnik to have a dedicated MSSQL driver, but notice that it does have support for OGR datasources and, since GDAL 1.8 supports MSSQLSpatial as a datasource (http://www.gdal.org/ogr/drv_mssqlspatial.html), I thought I'd be able to connect via that. So, I tried defining a VRT virtual layer that retrieved the Well-Known Text of one layer, as follows: <OGRVRTDataSource> <OGRVRTLayer name="AASQLlayer"> <SrcDataSource>MSSQL:server=.\SQLEXPRESS;database=OSVectorMap;trusted_connec tion=yes</SrcDataSource> <SrcSQL>SELECT geom27700.STAsText() AS geomWKT FROM TG11_Settlement_Area</SrcSQL> <GeometryField encoding="WKT" field="geomWKT"/> </OGRVRTLayer> </OGRVRTDataSource> Testing the OVF file above with ogrinfo seemed to suggest that the connection string was ok, and reported the following: C:\OSGeo4W\apps\mapnik\alastair\python>ogrinfo -so -al mssql.ovf INFO: Open of `mssql.ovf' using driver `VRT' successful. Layer name: AASQLlayer Geometry: Unknown (any) Feature Count: 1488 Extent: (610000.000001, 309999.999990) - (620000.000001, 319999.999992) Layer SRS WKT: (unknown) geomWKT: String (0.0) I then used this VRT as the datasource of a new layer in the rundemo.py script: new_lyr.datasource = mapnik.Ogr(file='MSSQL.ovf',layer="AASQLlayer") However, trying to render the map gave me the following error: ERROR 1: Failed to open datasource `MSSQL:server=.\SQLEXPRESS;database=OSVectorM ap;trusted_connection=yes'. Traceback (most recent call last): File "rundemo.py", line 73, in <module> provlines_lyr.datasource = mapnik.Ogr(file='MSSQL.ovf',layer="AASQLlayer") File "C:\OSGeo4W\apps\Python25\lib\site-packages\mapnik\__init__.py", line 418 , in Ogr return CreateDatasource(keywords) RuntimeError: Failed to open datasource `MSSQL:server=.\SQLEXPRESS;database=OSVe ctorMap;trusted_connection=yes'. I've tried various combinations of changing the VRT to return WKT, WKB, or SQL Server's own native geometry format - they all seem to validate ok with ogrinfo, but fail in mapnik. Could anyone please offer any advice as to how to connect mapnik to SQL Server? Thanks all for your time.
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