centroid()

Datum centroid

(

PG_FUNCTION_ARGS

)

Definition at line 1348 of file postgis/lwgeom_geos.c.

References CIRCSTRINGTYPE, COMPOUNDTYPE, dumpnode::geom, geometry_serialize(), GEOS2POSTGIS(), gserialized_get_srid(), gserialized_get_type(), gserialized_has_m(), gserialized_has_z(), gserialized_is_empty(), HANDLE_GEOS_ERROR, lwgeom_free(), lwgeom_from_gserialized(), lwgeom_geos_error(), lwgeom_stroke(), lwpoint_as_lwgeom(), lwpoint_construct_empty(), lwpoint_free(), PG_FUNCTION_INFO_V1(), POSTGIS2GEOS(), ST_ClipByBox2d(), and ovdump::type.

Referenced by lwgeom_centroid(), lwgeom_cluster_2d_kmeans(), and pointonsurface().

{
        GSERIALIZED *geom, *result;
        GEOSGeometry *geosgeom, *geosresult;
        LWGEOM *igeom = NULL, *linear_geom = NULL;
        int32 perQuad= 16;
        int type = 0;
        geom = PG_GETARG_GSERIALIZED_P(0);

        /* Empty.Centroid() == 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);
        }

        type = gserialized_get_type(geom) ;
        /* Converting curve geometry to linestring if necessary*/
        if(type == CIRCSTRINGTYPE || type == COMPOUNDTYPE )
        {/* curve geometry?*/
                igeom = lwgeom_from_gserialized(geom);
                PG_FREE_IF_COPY(geom, 0); /*free memory, we already have a lwgeom geometry copy*/
                linear_geom = lwgeom_stroke(igeom, perQuad);
                lwgeom_free(igeom);
                if (linear_geom == NULL)
                        PG_RETURN_NULL();

                geom = geometry_serialize(linear_geom);
                lwgeom_free(linear_geom);
        }

        initGEOS(lwpgnotice, lwgeom_geos_error);

        geosgeom = (GEOSGeometry *)POSTGIS2GEOS(geom);

        if ( 0 == geosgeom )   /* exception thrown at construction */
        {
                HANDLE_GEOS_ERROR("First argument geometry could not be converted to GEOS");
                PG_RETURN_NULL();
        }

        geosresult = GEOSGetCentroid(geosgeom);

        if ( geosresult == NULL )
        {
                GEOSGeom_destroy(geosgeom);
                HANDLE_GEOS_ERROR("GEOSGetCentroid");
                PG_RETURN_NULL();
        }

        GEOSSetSRID(geosresult, gserialized_get_srid(geom));

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

        if (result == NULL)
        {
                GEOSGeom_destroy(geosgeom);
                GEOSGeom_destroy(geosresult);
                elog(ERROR,"Error in GEOS-PGIS conversion");
                PG_RETURN_NULL();
        }
        GEOSGeom_destroy(geosgeom);
        GEOSGeom_destroy(geosresult);

        PG_FREE_IF_COPY(geom, 0);

        PG_RETURN_POINTER(result);
}

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