protected void showGridSightLines(List<Position> grid, Position cPos) {
      this.sightLinesLayer.removeAllRenderables();

      // Display lines from the center to each grid point.
      ShapeAttributes lineAttributes;
      lineAttributes = new BasicShapeAttributes();
      lineAttributes.setDrawOutline(true);
      lineAttributes.setDrawInterior(false);
      lineAttributes.setOutlineMaterial(Material.GREEN);
      lineAttributes.setOutlineOpacity(0.6);

      for (Position p : grid) {
        List<Position> endPoints = new ArrayList<Position>();
        endPoints.add(cPos);
        endPoints.add(new Position(p.getLatitude(), p.getLongitude(), 0));

        Path path = new Path(endPoints);
        path.setAltitudeMode(WorldWind.RELATIVE_TO_GROUND);
        path.setAttributes(lineAttributes);
        this.sightLinesLayer.addRenderable(path);
      }
    }
    protected void showSightLines(List<Position[]> sightLines) {
      this.sightLinesLayer.removeAllRenderables();

      // Display the sight lines as green lines.
      ShapeAttributes lineAttributes;
      lineAttributes = new BasicShapeAttributes();
      lineAttributes.setDrawOutline(true);
      lineAttributes.setDrawInterior(false);
      lineAttributes.setOutlineMaterial(Material.GREEN);
      lineAttributes.setOutlineOpacity(0.6);

      for (Position[] pp : sightLines) {
        List<Position> endPoints = new ArrayList<Position>();
        endPoints.add(pp[0]);
        endPoints.add(pp[1]);

        Path path = new Path(endPoints);
        path.setAltitudeMode(WorldWind.RELATIVE_TO_GROUND);
        path.setAttributes(lineAttributes);
        this.sightLinesLayer.addRenderable(path);
      }
    }