lwmpoly_to_points()

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

Definition at line 1872 of file liblwgeom/lwgeom_geos.c.

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().

{
        const LWGEOM *lwgeom = (LWGEOM*)lwmpoly;
        double area;
        int 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
                        {
                                int 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 owed by the returning multipoint */
                                lwfree(sub_mpt->geoms);
                                lwgeom_release((LWGEOM*)sub_mpt);
                        }
                }
        }

        return mpt;
}

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