ST_CoverageUnion()

Datum ST_CoverageUnion

(

PG_FUNCTION_ARGS

)

Definition at line 796 of file lwgeom_window.c.

{
#if POSTGIS_GEOS_VERSION < 30800
        lwpgerror("The GEOS version this PostGIS binary "
                "was compiled against (%d) doesn't support "
                "'GEOSCoverageUnion' function (3.8.0+ required)",
                POSTGIS_GEOS_VERSION);
        PG_RETURN_NULL();
 
#else /* POSTGIS_GEOS_VERSION >= 30800 */
 
        GSERIALIZED *result = NULL;
 
        Datum value;
        bool isnull;
 
        GEOSGeometry **geoms = NULL;
        GEOSGeometry *geos = NULL;
        GEOSGeometry *geos_result = NULL;
        uint32 ngeoms = 0;
 
        ArrayType *array = PG_GETARG_ARRAYTYPE_P(0);
        uint32 nelems = ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array));
        ArrayIterator iterator = array_create_iterator(array, 0, NULL);
 
        /* Return null on 0-elements input array */
        if (nelems == 0)
                PG_RETURN_NULL();
 
        /* Convert all geometries into GEOSGeometry array */
        geoms = palloc(sizeof(GEOSGeometry *) * nelems);
 
        initGEOS(lwpgnotice, lwgeom_geos_error);
 
        while (array_iterate(iterator, &value, &isnull))
        {
                GSERIALIZED *gser;
                /* Omit nulls */
                if (isnull) continue;
 
                /* Omit empty */
                gser = (GSERIALIZED *)DatumGetPointer(value);
                if (gserialized_is_empty(gser)) continue;
 
                /* Omit unconvertable */
                geos = POSTGIS2GEOS(gser);
                if (!geos) continue;
 
                geoms[ngeoms++] = geos;
        }
        array_free_iterator(iterator);
 
        if (ngeoms == 0)
                PG_RETURN_NULL();
 
        geos = GEOSGeom_createCollection(
                GEOS_GEOMETRYCOLLECTION,
                geoms, ngeoms);
 
        if (!geos)
        {
                coverage_destroy_geoms(geoms, ngeoms);
                HANDLE_GEOS_ERROR("Geometry could not be converted");
        }
 
        geos_result = GEOSCoverageUnion(geos);
        GEOSGeom_destroy(geos);
        if (!geos_result)
                HANDLE_GEOS_ERROR("Error computing coverage union");
 
        result = GEOS2POSTGIS(geos_result, LW_FALSE);
        GEOSGeom_destroy(geos_result);
 
        PG_RETURN_POINTER(result);
#endif
}

References coverage_destroy_geoms(), GEOS2POSTGIS(), gserialized_is_empty(), HANDLE_GEOS_ERROR, LW_FALSE, lwgeom_geos_error(), POSTGIS2GEOS(), POSTGIS_GEOS_VERSION, result, and genraster::value.

Referenced by pgis_geometry_coverageunion_finalfn().

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