[gdal-dev] OGRGeometry Distance

Frank Warmerdam warmerdam at pobox.com
Mon Sep 21 15:12:56 EDT 2009

Yilmaz Arslanoglu wrote:
> Also, as another related question, I query the DEPCNT  layer in one of
> my ENC files, and it has a geospatial reference.
> However, the points on the line string features themselves return NULL
> when they are queried with getSpatialReference().
> Aren't they expected to return exactly the same instance for the layer
> that they reside on?


Others have addressed the geodesic distance issue.

On the spatial reference issue, you are correct.  The geometry from the
layers ought to return a pointer to the same spatial reference object
as you see on the layer.  It is a defect of the S-57 driver (and I suspect
a number of others) that this is not done.  If you like, you could file
a ticket on this and someone could fix it up.

In practice the spatial references attached to the geometries are rarely
consulted by applications and so are often not set properly by drivers.

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    | Geospatial Programmer for Rent

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