[Gdal-dev] SDE Implementation
Yewondwossen Assefa
assefa at DMSOLUTIONS.CA
Fri Nov 25 12:16:24 PST 2005
This info maybe of interest to the list.
Are the capabilities more or less similar between the mapserver
implemenation and the OGR one ?
Thanks,
Frank Warmerdam wrote:
> Howard,
>
> I have now have the essentials of the read-only SDE vector driver
> complete. This includes:
> o Getting list of layers (tables) from registration info
> o Support for the attribute field types supported by mapsde.c,
> including date, and blob.
> o Support for fast GetFeature() fetching the row by rowid.
> o Support for fast spatial extents from layerinfo.
> o Support for relatively fast feature counting using a fetch
> of only the feature ids.
> o Support for fast spatial query using spatial constraints on stream.
> o Support for fast attribute filtering using queryinfo where clause.
> o Support for reading coordinate system (from layerinfo).
> o Support for point, line and polygon geometries (2d or 3d).
> o I avoid fetching the layerinfo unless needed. Normally just for
> layers that are actively queried rather than all layers in the
> datasource.
> o Configuration logic on unix (similar to MapServer config options).
>
> Still needed:
> o Support for multi-point, multi-line and multi-polygon geometries.
> o Support for esoteric field types (XML, etc).
> o Logic to pass layers names, shape column, and fid column in the
> datasource names.
> o Build support on windows.
> o Review annotation and "cad' data objects for possible support.
>
> Testing needed:
> o With no coordref.
> o Odd field types (blob, date, etc).
> o Tables with no geometry?
> o Tables with multiple geometry columns.
> o datasources with no registration info (SDE for Coverages).
> o test with 3D layers.
> o test with measured layers (measures to be ignored).
>
> All in all the SDE API is pretty straight forward, and this has
> been a surprisingly pleasant activity. Of course, in large part
> that is due to your providing a setup server, and providing
> me with good documentation.
>
> If you are feeling ambitious, feel free to try building and
> testing things a bit.
>
> 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 | Geospatial Programmer for Rent
>
> _______________________________________________
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> Gdal-dev at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/gdal-dev
>
--
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Assefa Yewondwossen
Software Analyst
Email: assefa at dmsolutions.ca
http://www.dmsolutions.ca/
Phone: (613) 565-5056 (ext 14)
Fax: (613) 565-0925
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