[gdal-dev] OGR_G_ExportToWkt make MEX crash

[Joaquim Luis]

On 06-09-2011 17:48, Frank Warmerdam wrote:
> 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,ject

OK, that's what I assumed too and the root of my error when tried to 
call OGR_G_ExportToWkt on a spatial reference object.

Thanks again

Joaquim