convexhull()

Datum convexhull

(

PG_FUNCTION_ARGS

)

Definition at line 686 of file postgis/lwgeom_geos.c.

{
        GSERIALIZED *geom1;
        GEOSGeometry *g1, *g3;
        GSERIALIZED *result;
        LWGEOM *lwout;
        int srid;
        GBOX bbox;
 
        geom1 = PG_GETARG_GSERIALIZED_P(0);
 
        /* Empty.ConvexHull() == Empty */
        if ( gserialized_is_empty(geom1) )
                PG_RETURN_POINTER(geom1);
 
        srid = gserialized_get_srid(geom1);
 
        initGEOS(lwpgnotice, lwgeom_geos_error);
 
        g1 = POSTGIS2GEOS(geom1);
 
        if (!g1)
                HANDLE_GEOS_ERROR("First argument geometry could not be converted to GEOS");
 
        g3 = GEOSConvexHull(g1);
        GEOSGeom_destroy(g1);
 
        if (!g3) HANDLE_GEOS_ERROR("GEOSConvexHull");
 
        POSTGIS_DEBUGF(3, "result: %s", GEOSGeomToWKT(g3));
 
        GEOSSetSRID(g3, srid);
 
        lwout = GEOS2LWGEOM(g3, gserialized_has_z(geom1));
        GEOSGeom_destroy(g3);
 
        if (!lwout)
        {
                elog(ERROR,
                     "convexhull() failed to convert GEOS geometry to LWGEOM");
                PG_RETURN_NULL(); /* never get here */
        }
 
        /* Copy input bbox if any */
        if ( gserialized_get_gbox_p(geom1, &bbox) )
        {
                /* Force the box to have the same dimensionality as the lwgeom */
                bbox.flags = lwout->flags;
                lwout->bbox = gbox_copy(&bbox);
        }
 
        result = geometry_serialize(lwout);
        lwgeom_free(lwout);
 
        if (!result)
        {
                elog(ERROR,"GEOS convexhull() threw an error (result postgis geometry formation)!");
                PG_RETURN_NULL(); /* never get here */
        }
 
        PG_FREE_IF_COPY(geom1, 0);
        PG_RETURN_POINTER(result);
}

References LWGEOM::bbox, GBOX::flags, LWGEOM::flags, gbox_copy(), geometry_serialize(), GEOS2LWGEOM(), gserialized_get_gbox_p(), gserialized_get_srid(), gserialized_has_z(), gserialized_is_empty(), HANDLE_GEOS_ERROR, lwgeom_free(), lwgeom_geos_error(), and POSTGIS2GEOS().

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