[gdal-dev] OGR_G_ExportToWkt make MEX crash

[Frank Warmerdam]

On Tue, Sep 6, 2011 at 8:48 AM, Joaquim Luis <jluis at ualg.pt> wrote:
>
>> OGR_G_* functions are intended to operate on OGRGeometry objects while
>> OSR* functions operate on OGRSpatialReferences.  Your hSRS object is an
>> OGRSpatialReference and not suitable to pass to OGR_G_ExportToWkt().
>>
>> You should use OSRExportToWkt() to translate an OGRSpatialReference into
>> it's
>> WKT representation.
>>
>> Best regards,
>
> Thanks Frank.
>
> This is also a result of my attempt to understand all the OGR model plus
> inventing a way of wrapping it all inside a single StructureArray (the C-MEX
> API). So let me ask one further question about the model. Is is possible to
> have the case
>
> Dataset --> SRS
>               --> Feature1 --> Geom1 --> SRS1
>               --> Feature2 --> Geom2 --> SRS2
>               --> ...
>
> that is, different SpatialReferences inside the same Dataset?

Joaquim,

While not nailed down strictly, it is expected that
all geometries in a layer will share the same coordinate
system.  It is however common for the geometries
to be lacking the spatial reference object even though it
is set on the layer.

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 Software Developer