[gdal-dev] Ogr: Is an OGR::Geometry::InteriorPoint() method ?

[Even Rouault]

Selon Benjamin <benjamin.lux at maxsea.fr>:

> Hi,
>
> Is an OGR::Geometry method which compute an interior point exist ?

To my knowledge there is no such method. If you don't have particular
constraints on the point except that it must be at the interior of the polygon,
you could take a random vertex of the boundary, compute the distance D to the
next point, and then compute various points located on a circle centered on that
vertex and of radius D/2 until the IsPointOnSurface() returns TRUE. Not very
efficient, there are likely better methods...

> I have just found a Centroid() method but "The centroid is not necessarily
> within the geometry".
>
> So the centroid of:
> POLYGON ((0 0,0 5, 5 5, 5 4, 1 4, 1 1, 5 1, 5 0, 0 0)) is near to (2 2.5),
> it's within the polygon.
>  _____
> |   ___|
> |  |___
> |_____|
>
> (ASCII fan-art o/)
>
> For example, with JTS (Java Topologie Suite) we can obtain an interior point
> (0.5 2.5).

Do you know the name of the JTS method ? It might also exist in GEOS, the C++
port of JTS that GDAL relies on to do geometry related computations.