void simplify() {
      if (pipeline != null) {
        coordinates = List.of(
          pipeline.apply(GeoUtils.JTS_FACTORY.createLineString(coordinates.toArray(Coordinate[]::new)))
            .getCoordinates());
      } else if (tolerance >= 0) {
        coordinates = DouglasPeuckerSimplifier.simplify(coordinates, tolerance, false);
      }
      if (reversed != null) {
        reversed.coordinates = coordinates.reversed();
      }
    }
Processes the added geometries and returns the merged linestrings.
<p>
Can be called more than once.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/LoopLineMerger.java