[Gdal-dev] SDE Driver Change

Frank Warmerdam warmerdam at pobox.com
Thu Oct 26 14:15:02 EDT 2006

Christian Ratliff wrote:
>   During the QA process for our product, we noticed polygons were being 
> read from ARC/SDE with a reversed (left hand) winding.  This results in 
> isClockwise() returning the wrong value for all such polygons.  I 
> updated the SDE driver with the change indicated below and then 
> re-tested SDE and non-SDE data sources.  Everything looks good now:
> src/ogr/ogrsf_formats/sde/ogrsdelayer.cpp
> 719c723
> <     nSDEErr = SE_shape_get_all_points( hShape, SE_DEFAULT_ROTATION,
> ---
>>     nSDEErr = SE_shape_get_all_points( hShape, SE_RIGHT_HAND_ROTATION,


There is no harm in doing this, but I would note that OGRPolygon rings
are not guaranteed to have any particular handedness.  So it is unwise
to build application on this assumption.

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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