[Proj] pj_transform arguments

Frank Warmerdam warmerdam at pobox.com
Tue Aug 21 13:56:08 EDT 2007

Sue Dettling wrote:
> Hi,
> I just installed the debian version of the library.
> The man pages are out of date with the argument list
> for pj_transform. Can you tell me what the data_offset
> is ?


I assume you mean "point_offset"?

int pj_transform( PJ *srcdefn, PJ *dstdefn, long point_count, int point_offset,
                   double *x, double *y, double *z )

In this case point_offset is the step size to use from one value to the
next in x, y and z arrays.  Normally this is 1, indicating that the values
are tightly packed one after the other.  But some folks have their values
in arrays of x/y/z interleaved, so they might pass a point_offset value
of three.

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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