lwgeom_centroid()

LWGEOM* lwgeom_centroid

(

const LWGEOM *

geom

)

Definition at line 943 of file liblwgeom/lwgeom_geos.c.

References centroid(), GEOS2LWGEOM(), LWDEBUGF, lwerror(), LWGEOM2GEOS(), lwgeom_geos_errmsg, lwgeom_geos_error(), lwgeom_get_srid(), lwgeom_has_m(), lwgeom_has_z(), lwgeom_is_empty(), lwnotice(), lwpoint_as_lwgeom(), and lwpoint_construct_empty().

Referenced by lwgeom_cluster_2d_kmeans().

{
        GEOSGeometry *g, *g_centroid;
        LWGEOM *centroid;
        int srid, is3d;

        if (lwgeom_is_empty(geom))
        {
                LWPOINT *lwp = lwpoint_construct_empty(
                                   lwgeom_get_srid(geom),
                                   lwgeom_has_z(geom),
                                   lwgeom_has_m(geom));
                return lwpoint_as_lwgeom(lwp);
        }

        srid = lwgeom_get_srid(geom);
        is3d = lwgeom_has_z(geom);

        initGEOS(lwnotice, lwgeom_geos_error);

        g = LWGEOM2GEOS(geom, 0);

        if (0 == g)   /* exception thrown at construction */
        {
                lwerror("Geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
                return NULL;
        }

        g_centroid = GEOSGetCentroid(g);
        GEOSGeom_destroy(g);

        if (g_centroid == NULL)
        {
                lwerror("GEOSGetCentroid: %s", lwgeom_geos_errmsg);
                return NULL; /*never get here */
        }

        LWDEBUGF(3, "result: %s", GEOSGeomToWKT(g_centroid));

        GEOSSetSRID(g_centroid, srid);

        centroid = GEOS2LWGEOM(g_centroid, is3d);
        GEOSGeom_destroy(g_centroid);

        if (centroid == NULL)
        {
                lwerror("GEOS GEOSGetCentroid() threw an error (result postgis geometry formation)!");
                return NULL ; /*never get here */
        }

        return centroid;
}

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