pointonsurface()

Datum pointonsurface

(

PG_FUNCTION_ARGS

)

Definition at line 1284 of file postgis/lwgeom_geos.c.

References centroid(), dumpnode::geom, geometry_serialize(), GEOS2POSTGIS(), gserialized_get_srid(), gserialized_has_m(), gserialized_has_z(), gserialized_is_empty(), HANDLE_GEOS_ERROR, lwgeom_geos_errmsg, lwgeom_geos_error(), lwpoint_as_lwgeom(), lwpoint_construct_empty(), lwpoint_free(), PG_FUNCTION_INFO_V1(), and POSTGIS2GEOS().

Referenced by geos_difference().

{
        GSERIALIZED *geom;
        GEOSGeometry *g1, *g3;
        GSERIALIZED *result;

        geom = PG_GETARG_GSERIALIZED_P(0);

        /* Empty.PointOnSurface == Point Empty */
        if ( gserialized_is_empty(geom) )
        {
                LWPOINT *lwp = lwpoint_construct_empty(
                                   gserialized_get_srid(geom),
                                   gserialized_has_z(geom),
                                   gserialized_has_m(geom));
                result = geometry_serialize(lwpoint_as_lwgeom(lwp));
                lwpoint_free(lwp);
                PG_RETURN_POINTER(result);
        }

        initGEOS(lwpgnotice, lwgeom_geos_error);

        g1 = (GEOSGeometry *)POSTGIS2GEOS(geom);

        if ( 0 == g1 )   /* exception thrown at construction */
        {
                /* Why is this a WARNING rather than an error ? */
                /* TODO: use HANDLE_GEOS_ERROR instead */
                elog(WARNING, "GEOSPointOnSurface(): %s", lwgeom_geos_errmsg);
                PG_RETURN_NULL();
        }

        g3 = GEOSPointOnSurface(g1);

        if (g3 == NULL)
        {
                GEOSGeom_destroy(g1);
                HANDLE_GEOS_ERROR("GEOSPointOnSurface");
                PG_RETURN_NULL(); /* never get here */
        }

        POSTGIS_DEBUGF(3, "result: %s", GEOSGeomToWKT(g3) ) ;

        GEOSSetSRID(g3, gserialized_get_srid(geom));

        result = GEOS2POSTGIS(g3, gserialized_has_z(geom));

        if (result == NULL)
        {
                GEOSGeom_destroy(g1);
                GEOSGeom_destroy(g3);
                elog(ERROR,"GEOS pointonsurface() threw an error (result postgis geometry formation)!");
                PG_RETURN_NULL(); /* never get here */
        }

        GEOSGeom_destroy(g1);
        GEOSGeom_destroy(g3);

        PG_FREE_IF_COPY(geom, 0);

        PG_RETURN_POINTER(result);
}

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