Google Earth API Samples - Getting Viewport Globe Bounds

Bounding Box via getViewportGlobeBounds()
Bounding Box via hitTest()
   Note: if either of the four plugin corners return a null hitTest, the red polygon won't appear.

Relevant Resources:

• GEView Reference
• google.earth Namespace Reference
• KmlEvent Reference
• Maps API GPolygon Reference

Relevant Code Excerpt:

// just for comparison
ge.getOptions().setOverviewMapVisibility(true);

google.earth.addEventListener(ge.getView(), 'viewchange', function(evt) {
  map.clearOverlays();
  
  var totalBounds = new GLatLngBounds();
  
  // get the globe bounds (method 1)
  var globeBounds = ge.getView().getViewportGlobeBounds();
  var fakeBoundsCenter = null;
  
  if (globeBounds) {
    globeBounds.setNorth(Math.min(globeBounds.getNorth(), 85));
    globeBounds.setSouth(Math.max(globeBounds.getSouth(), -85));
    
    if (globeBounds.getEast() == 180 && globeBounds.getWest() == -180) {
      fakeBoundsCenter = new GLatLng(0, 0);
      var globeBoundsPolygon = new GPolygon([
          new GLatLng(globeBounds.getNorth(), -179),
          new GLatLng(globeBounds.getNorth(), 0),
          new GLatLng(globeBounds.getNorth(), 179),
          new GLatLng(globeBounds.getSouth(), 179),
          new GLatLng(globeBounds.getSouth(), 0),
          new GLatLng(globeBounds.getSouth(), -179),
          new GLatLng(globeBounds.getNorth(), -179)],
          '#0000ff', 2, 1.00,
          '#0000ff',    0.25,
          { clickable: false });
    } else {
      var globeBoundsPolygon = new GPolygon([
          new GLatLng(globeBounds.getNorth(), globeBounds.getWest()),
          new GLatLng(globeBounds.getNorth(), globeBounds.getEast()),
          new GLatLng(globeBounds.getSouth(), globeBounds.getEast()),
          new GLatLng(globeBounds.getSouth(), globeBounds.getWest()),
          new GLatLng(globeBounds.getNorth(), globeBounds.getWest())],
          '#0000ff', 2, 1.00,
          '#0000ff',    0.25,
          { clickable: false });
    }
    
    map.addOverlay(globeBoundsPolygon);
    
    var polyBounds = globeBoundsPolygon.getBounds();
    totalBounds.extend(polyBounds.getNorthEast());
    totalBounds.extend(polyBounds.getSouthWest());
  }
  
  // hit test the corners (method 2)
  var hitTestTL = ge.getView().hitTest(0, ge.UNITS_FRACTION, 0, ge.UNITS_FRACTION, ge.HIT_TEST_GLOBE);
  var hitTestTR = ge.getView().hitTest(1, ge.UNITS_FRACTION, 0, ge.UNITS_FRACTION, ge.HIT_TEST_GLOBE);
  var hitTestBR = ge.getView().hitTest(1, ge.UNITS_FRACTION, 1, ge.UNITS_FRACTION, ge.HIT_TEST_GLOBE);
  var hitTestBL = ge.getView().hitTest(0, ge.UNITS_FRACTION, 1, ge.UNITS_FRACTION, ge.HIT_TEST_GLOBE);
  
  // ensure that all hit tests succeeded (i.e. the viewport is 2d-mappable)
  if (hitTestTL && hitTestTR && hitTestBL && hitTestBR) {
    var hitTestBoundsPolygon = new GPolygon([
        new GLatLng(hitTestTL.getLatitude(), hitTestTL.getLongitude()),
        new GLatLng(hitTestTR.getLatitude(), hitTestTR.getLongitude()),
        new GLatLng(hitTestBR.getLatitude(), hitTestBR.getLongitude()),
        new GLatLng(hitTestBL.getLatitude(), hitTestBL.getLongitude()),
        new GLatLng(hitTestTL.getLatitude(), hitTestTL.getLongitude())],
        '#ff0000', 2, 1.00,
        '#ff0000',    0.25,
        { clickable: false });
    map.addOverlay(hitTestBoundsPolygon);

    var polyBounds = hitTestBoundsPolygon.getBounds();
    totalBounds.extend(polyBounds.getNorthEast());
    totalBounds.extend(polyBounds.getSouthWest());
  }
  
  if (!totalBounds.isEmpty()) {
    map.setCenter(fakeBoundsCenter ? fakeBoundsCenter : totalBounds.getCenter(),
        map.getBoundsZoomLevel(totalBounds));
  }
});