[Gdal-dev] hi, does GDAL supports shapefile?

[Frank Warmerdam]

On 1/16/06, Jason <jason.wangz at gmail.com> wrote:
> hi, thanks for the replies.
>
> I have another problem.
> As for OGRPolygon Class Reference, there has a method name: virtual
> int  PointOnSurface (OGRPoint *poPoint) const
>
> Is this method provides a polygon point array? But how can I know
> about the total number of OGRPoint objects in this point array?

Jeshua,

Currently the implementation of this method looks like:

/************************************************************************/
/*                           PointOnSurface()                           */
/************************************************************************/

int OGRPolygon::PointOnSurface( OGRPoint * ) const

{
    // notdef ... not implemented yet.

    return OGRERR_FAILURE;
}

that is, there is no implementation.

The intention was that you would pass in a pointer
to an existing OGRPoint object, and this would be
reinitialized with a point on the surface.

I think I had expected to implement this using GEOS
but looking know I don't see an obvious way to implement
it using the GEOS C API.  Perhaps I could use the centroid
function, but it isn't clear to me that the centroid is guaranteed
to be on the surface.

Best regards,
--
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