RASTER_getPolygon()

Datum RASTER_getPolygon

(

PG_FUNCTION_ARGS

)

Definition at line 658 of file rtpg_geometry.c.

{
        rt_pgraster *pgraster = NULL;
        rt_raster raster = NULL;
        int num_bands = 0;
        int nband = 1;
        int err;
        LWMPOLY *surface = NULL;
        GSERIALIZED *rtn = NULL;
 
        /* raster */
        if (PG_ARGISNULL(0))
                PG_RETURN_NULL();
        pgraster = (rt_pgraster *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
 
        raster = rt_raster_deserialize(pgraster, FALSE);
        if (!raster) {
                PG_FREE_IF_COPY(pgraster, 0);
                elog(ERROR, "RASTER_getPolygon: Could not deserialize raster");
                PG_RETURN_NULL();
        }
 
        /* num_bands */
        num_bands = rt_raster_get_num_bands(raster);
        if (num_bands < 1) {
                elog(NOTICE, "Raster provided has no bands");
                rt_raster_destroy(raster);
                PG_FREE_IF_COPY(pgraster, 0);
                PG_RETURN_NULL();
        }
 
        /* band index is 1-based */
        if (!PG_ARGISNULL(1))
                nband = PG_GETARG_INT32(1);
        if (nband < 1 || nband > num_bands) {
                elog(NOTICE, "Invalid band index (must use 1-based). Returning NULL");
                rt_raster_destroy(raster);
                PG_FREE_IF_COPY(pgraster, 0);
                PG_RETURN_NULL();
        }
 
        /* get band surface */
        err = rt_raster_surface(raster, nband - 1, &surface);
        rt_raster_destroy(raster);
        PG_FREE_IF_COPY(pgraster, 0);
 
        if (err != ES_NONE) {
                elog(ERROR, "RASTER_getPolygon: Could not get raster band's surface");
                PG_RETURN_NULL();
        }
        else if (surface == NULL) {
                elog(NOTICE, "Raster is empty or all pixels of band are NODATA. Returning NULL");
                PG_RETURN_NULL();
        }
 
        rtn = geometry_serialize(lwmpoly_as_lwgeom(surface));
        lwmpoly_free(surface);
 
        PG_RETURN_POINTER(rtn);
}

References ES_NONE, FALSE, geometry_serialize(), lwmpoly_as_lwgeom(), lwmpoly_free(), rt_raster_deserialize(), rt_raster_destroy(), rt_raster_get_num_bands(), and rt_raster_surface().

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