[Gdal-dev] SDE Implementation

[Frank Warmerdam]

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,
--
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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