lwmpoly_to_points()

LWMPOINT* lwmpoly_to_points	(	const LWMPOLY *	mpoly,
		uint32_t	npoints
	)

Definition at line 1664 of file liblwgeom/lwgeom_geos.c.

{
        const LWGEOM* lwgeom = (LWGEOM*)lwmpoly;
        double area;
        uint32_t i;
        LWMPOINT* mpt = NULL;
 
        if (lwgeom_get_type(lwgeom) != MULTIPOLYGONTYPE)
        {
                lwerror("%s: only multipolygons supported", __func__);
                return NULL;
        }
        if (npoints == 0 || lwgeom_is_empty(lwgeom)) return NULL;
 
        area = lwgeom_area(lwgeom);
 
        for (i = 0; i < lwmpoly->ngeoms; i++)
        {
                double sub_area = lwpoly_area(lwmpoly->geoms[i]);
                int sub_npoints = lround(npoints * sub_area / area);
                if (sub_npoints > 0)
                {
                        LWMPOINT* sub_mpt = lwpoly_to_points(lwmpoly->geoms[i], sub_npoints);
                        if (!mpt)
                                mpt = sub_mpt;
                        else
                        {
                                uint32_t j;
                                for (j = 0; j < sub_mpt->ngeoms; j++)
                                        mpt = lwmpoint_add_lwpoint(mpt, sub_mpt->geoms[j]);
                                /* Just free the shell, leave the underlying lwpoints alone, as they are now owned by
                                 * the returning multipoint */
                                lwfree(sub_mpt->geoms);
                                lwgeom_release((LWGEOM*)sub_mpt);
                        }
                }
        }
        return mpt;
}

References area(), LWMPOINT::geoms, LWMPOLY::geoms, lwerror(), lwfree(), lwgeom_area(), lwgeom_get_type(), lwgeom_is_empty(), lwgeom_release(), lwmpoint_add_lwpoint(), lwpoly_area(), lwpoly_to_points(), MULTIPOLYGONTYPE, LWMPOINT::ngeoms, and LWMPOLY::ngeoms.

Referenced by lwgeom_to_points().

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