示例#1
0
  /**
   * Compute the lat/lon position of the view center
   *
   * @param dc the current DrawContext
   * @param view the current View
   * @return the ground position of the view center or null
   */
  protected Position computeGroundPosition(DrawContext dc, View view) {
    if (view == null) return null;

    Position groundPos =
        view.computePositionFromScreenPoint(
            view.getViewport().getWidth() / 2, view.getViewport().getHeight() / 2);
    if (groundPos == null) return null;

    double elevation =
        dc.getGlobe().getElevation(groundPos.getLatitude(), groundPos.getLongitude());
    return new Position(
        groundPos.getLatitude(),
        groundPos.getLongitude(),
        elevation * dc.getVerticalExaggeration());
  }
示例#2
0
 /**
  * Compute the view range footprint on the globe.
  *
  * @param dc the current <code>DrawContext</code>
  * @param steps the number of steps.
  * @return an array list of <code>LatLon</code> forming a closed shape.
  */
 protected ArrayList<LatLon> computeViewFootPrint(DrawContext dc, int steps) {
   ArrayList<LatLon> positions = new ArrayList<LatLon>();
   Position eyePos = dc.getView().getEyePosition();
   Angle distance =
       Angle.fromRadians(
           Math.asin(
               dc.getView().getFarClipDistance()
                   / (dc.getGlobe().getRadius() + eyePos.getElevation())));
   if (distance.degrees > 10) {
     double headStep = 360d / steps;
     Angle heading = Angle.ZERO;
     for (int i = 0; i <= steps; i++) {
       LatLon p = LatLon.greatCircleEndPosition(eyePos, heading, distance);
       positions.add(p);
       heading = heading.addDegrees(headStep);
     }
     return positions;
   } else return null;
 }