@Override
  protected void doRender(DrawContext dc) {
    this.referencePoint = this.computeReferencePoint(dc);

    int serviceCount = this.placeNameServiceSet.getServiceCount();
    for (int i = 0; i < serviceCount; i++) {
      PlaceNameService placeNameService = this.placeNameServiceSet.getService(i);
      if (!isServiceVisible(dc, placeNameService)) continue;

      double minDistSquared =
          placeNameService.getMinDisplayDistance() * placeNameService.getMinDisplayDistance();
      double maxDistSquared =
          placeNameService.getMaxDisplayDistance() * placeNameService.getMaxDisplayDistance();

      if (isSectorVisible(
          dc, placeNameService.getMaskingSector(), minDistSquared, maxDistSquared)) {
        ArrayList<Tile> baseTiles = new ArrayList<Tile>();
        NavigationTile navTile = this.navTiles.get(i);
        // drill down into tiles to find bottom level navTiles visible
        List<NavigationTile> list = navTile.navTilesVisible(dc, minDistSquared, maxDistSquared);
        for (NavigationTile nt : list) {
          baseTiles.addAll(nt.getTiles());
        }

        for (Tile tile : baseTiles) {
          try {
            drawOrRequestTile(dc, tile, minDistSquared, maxDistSquared);
          } catch (Exception e) {
            Logging.logger()
                .log(
                    Level.FINE,
                    Logging.getMessage("layers.PlaceNameLayer.ExceptionRenderingTile"),
                    e);
          }
        }
      }
    }

    this.sendRequests();
    this.requestQ.clear();
  }
  protected static boolean isNameVisible(
      DrawContext dc, PlaceNameService service, Position namePosition) {
    double elevation = dc.getVerticalExaggeration() * namePosition.getElevation();
    Vec4 namePoint =
        dc.getGlobe()
            .computePointFromPosition(
                namePosition.getLatitude(), namePosition.getLongitude(), elevation);
    Vec4 eyeVec = dc.getView().getEyePoint();

    double dist = eyeVec.distanceTo3(namePoint);
    return dist >= service.getMinDisplayDistance() && dist <= service.getMaxDisplayDistance();
  }