[gdal-dev] OGR 3D coordinates

[Andrew T. Louis]

Thanks a lot.
Just what I wanted to know

Thanks

-----Original Message-----
From: Frank Warmerdam [mailto:warmerdam at pobox.com] 
Sent: 7 février 2008 14:35
To: Andrew T. Louis
Cc: gdal-dev at lists.osgeo.org
Subject: Re: [gdal-dev] OGR 3D coordinates

Andrew T. Louis wrote:
> Hi all,
> Does the ogr2ogr tool handle composed WKT (datum + elevation=Z value)
> for CRS transformation?
> I tried with no success... 

Andrew,

Are you asking if GDAL/OGR supposed compound coordinate system
defining the Z axis in WKT?  The short answer is no.

> If it does, should the input coordinates only be 3D? Or will it ignore
> the Z value when transforming a 2D input?

The transform() method on OGRGeometries will assume a Z of zero before
calling the transformer which operates in 3D.  Reviewing the code quickly
it seems that in some cases (some types of geometry) the geometry may
be forced into 3D mode after the transform method.

Best regards,
-- 
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