lwgeom_buildarea()

LWGEOM* lwgeom_buildarea

(

const LWGEOM *

geom

)

Take a geometry and return an areal geometry (Polygon or MultiPolygon).

Actually a wrapper around GEOSpolygonize, transforming the resulting collection into a valid polygon Geometry.

Definition at line 1188 of file liblwgeom/lwgeom_geos.c.

References LWGEOM::flags, FLAGS_GET_Z, geos_clean(), geos_clean_and_fail(), get_result_srid(), input_lwgeom_to_geos(), LWGEOM_GEOS_buildArea(), lwgeom_geos_error(), lwgeom_is_empty(), lwnotice(), lwpoly_construct_empty(), output_geos_as_lwgeom(), and SRID_INVALID.

Referenced by _lwt_FaceByEdges(), buildarea1(), buildarea2(), buildarea3(), buildarea4(), buildarea4b(), buildarea5(), buildarea6(), buildarea7(), and ST_BuildArea().

{
        LWGEOM* result;
        int32_t srid = get_result_srid(geom, NULL, __func__);
        uint8_t is3d = FLAGS_GET_Z(geom->flags);
        GEOSGeometry *g1, *g3;

        if (srid == SRID_INVALID) return NULL;

        /* Can't build an area from an empty! */
        if (lwgeom_is_empty(geom)) return (LWGEOM*)lwpoly_construct_empty(srid, is3d, 0);

        initGEOS(lwnotice, lwgeom_geos_error);

        if (!input_lwgeom_to_geos(&g1, geom, __func__)) return NULL;

        g3 = LWGEOM_GEOS_buildArea(g1);

        if (!g3) return geos_clean_and_fail(g1, NULL, NULL, __func__);

        /* If no geometries are in result collection, return NULL */
        if (GEOSGetNumGeometries(g3) == 0) return geos_clean_and_fail(g1, NULL, NULL, __func__);

        if (!output_geos_as_lwgeom(&g3, &result, srid, is3d, __func__))
                return geos_clean_and_fail(g1, NULL, g3, __func__);

        geos_clean(g1, NULL, g3);

        return result;
}

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