if (resolution != null) {
width = (int) Math.ceil(bbox.width / resolution);
height = (int) Math.ceil(bbox.height / resolution);
}
TileRequest tileRequest = new TileRequest("", bbox, width, height);
SPTRequest sptRequest = new SPTRequest(x, y, time.cal);
RenderRequest renderRequest = new RenderRequest(format, Layer.TRAVELTIME, Style.GRAY, false, false);
return null; //renderer.getResponse(tileRequest, sptRequest, null, renderRequest);