CREATE OR REPLACE FUNCTION layer_kct(bbox geometry, zoom_level int)
RETURNS TABLE(geometry geometry, name text, waycolor text) AS $$
    SELECT geometry, NULLIF(name, '') AS name, SPLIT_PART(osmc_symbol, ':', 1) as waycolor
    FROM osm_kct_relation
    WHERE geometry && bbox;
$$ LANGUAGE SQL IMMUTABLE;
