lw_dist3d_point_poly()

int lw_dist3d_point_poly	(	const LWPOINT *	point,
		const LWPOLY *	poly,
		DISTPTS3D *	dl
	)

Computes point to polygon distance For mindistance that means: 1) find the plane of the polygon 2) projecting the point to the plane of the polygon 3) finding if that projected point is inside the polygon, if so the distance is measured to that projected point 4) if not in polygon above, check the distance against the boundary of the polygon for max distance it is always point against boundary.

Definition at line 778 of file measures3d.c.

{
        POINT3DZ p, projp; /*projp is "point projected on plane"*/
        PLANE3D plane;
        LWDEBUG(2, "lw_dist3d_point_poly is called");
        getPoint3dz_p(point->point, 0, &p);
 
        /* If we are looking for max distance, longestline or dfullywithin */
        if (dl->mode == DIST_MAX)
                return lw_dist3d_pt_ptarray(&p, poly->rings[0], dl);
 
        /* Find the plane of the polygon, the "holes" have to be on the same plane. so we only care about the boundary */
        if (!define_plane(poly->rings[0], &plane))
        {
                /* Polygon does not define a plane: Return distance point -> line */
                return lw_dist3d_pt_ptarray(&p, poly->rings[0], dl);
        }
 
        /* Get our point projected on the plane of the polygon */
        project_point_on_plane(&p, &plane, &projp);
 
        return lw_dist3d_pt_poly(&p, poly, &plane, &projp, dl);
}

References define_plane(), DIST_MAX, getPoint3dz_p(), lw_dist3d_pt_poly(), lw_dist3d_pt_ptarray(), LWDEBUG, DISTPTS3D::mode, LWPOINT::point, project_point_on_plane(), and LWPOLY::rings.

Referenced by lw_dist3d_distribute_bruteforce().

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