diff --git a/src/AIModel/AIAircraft.cxx b/src/AIModel/AIAircraft.cxx
index 6559bbcbd..a9e22a723 100644
--- a/src/AIModel/AIAircraft.cxx
+++ b/src/AIModel/AIAircraft.cxx
@@ -167,19 +167,9 @@ void FGAIAircraft::setPerformance(const std::string& acclass) {
 
 void FGAIAircraft::checkVisibility() 
 {
-     double visibility_meters = fgGetDouble("/environment/visibility-m");
-
-     FGViewer* vw = globals->get_current_view();
-     double course, distance;
-
-     SGWayPoint current(pos.getLongitudeDeg(), pos.getLatitudeDeg(), 0);
-     SGWayPoint view (vw->getLongitude_deg(), vw->getLatitude_deg(), 0);
-     view.CourseAndDistance(current, &course, &distance);
-     if (distance > visibility_meters) {
-         invisible = true;
-      } else {
-         invisible = false;
-      }
+  double visibility_meters = fgGetDouble("/environment/visibility-m");
+  FGViewer* vw = globals->get_current_view();
+  invisible = (SGGeodesy::distanceM(vw->getPosition(), pos) > visibility_meters);
 }
 
 
@@ -409,14 +399,9 @@ void FGAIAircraft::getGroundElev(double dt) {
     // Only do the proper hitlist stuff if we are within visible range of the viewer.
     if (!invisible) {
         double visibility_meters = fgGetDouble("/environment/visibility-m");
-
         FGViewer* vw = globals->get_current_view();
-        double course, distance;
-
-        SGWayPoint current(pos.getLongitudeDeg(), pos.getLatitudeDeg(), 0);
-        SGWayPoint view (vw->getLongitude_deg(), vw->getLatitude_deg(), 0);
-        view.CourseAndDistance(current, &course, &distance);
-        if (distance > visibility_meters) {
+        
+        if (SGGeodesy::distanceM(vw->getPosition(), pos) > visibility_meters) {
             return;
         }
 
diff --git a/src/ATCDCL/AILocalTraffic.cxx b/src/ATCDCL/AILocalTraffic.cxx
index 0e81570ae..4a5dfaa3b 100644
--- a/src/ATCDCL/AILocalTraffic.cxx
+++ b/src/ATCDCL/AILocalTraffic.cxx
@@ -1539,21 +1539,21 @@ void FGAILocalTraffic::DoGroundElev() {
 	// Only do the proper hitlist stuff if we are within visible range of the viewer.
 	double visibility_meters = fgGetDouble("/environment/visibility-m");
 	FGViewer* vw = globals->get_current_view();
-	if(dclGetHorizontalSeparation(_pos, SGGeod::fromDegM(vw->getLongitude_deg(), vw->getLatitude_deg(), 0.0)) > visibility_meters) {
+	if(dclGetHorizontalSeparation(_pos, SGGeod::fromGeodM(vw->getPosition(), 0.0)) > visibility_meters) {
 		_ground_elevation_m = aptElev;
 		return;
 	}
 
-        // FIXME: make shure the pos.lat/pos.lon values are in degrees ...
-        double range = 500.0;
-        if (!globals->get_tile_mgr()->scenery_available(_aip.getPosition(), range)) {
-          // Try to shedule tiles for that position.
-          globals->get_tile_mgr()->update( _aip.getPosition(), range );
-        }
+  // FIXME: make shure the pos.lat/pos.lon values are in degrees ...
+  double range = 500.0;
+  if (!globals->get_tile_mgr()->scenery_available(_aip.getPosition(), range)) {
+    // Try to shedule tiles for that position.
+    globals->get_tile_mgr()->update( _aip.getPosition(), range );
+  }
 
-        // FIXME: make shure the pos.lat/pos.lon values are in degrees ...
-        double alt;
-        if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(_aip.getPosition(), 20000), alt, 0))
-          _ground_elevation_m = alt;
+  // FIXME: make shure the pos.lat/pos.lon values are in degrees ...
+  double alt;
+  if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(_aip.getPosition(), 20000), alt, 0))
+    _ground_elevation_m = alt;
 }
 
diff --git a/src/Main/main.cxx b/src/Main/main.cxx
index c73123966..b864563ea 100644
--- a/src/Main/main.cxx
+++ b/src/Main/main.cxx
@@ -496,8 +496,7 @@ static void fgMainLoop( void ) {
 
     // get the orientation
     const SGQuatd view_or = current_view->getViewOrientation();
-    SGQuatd surf_or = SGQuatd::fromLonLatDeg(
-        current_view->getLongitude_deg(), current_view->getLatitude_deg());
+    SGQuatd surf_or = SGQuatd::fromLonLat(current_view->getPosition());
     SGQuatd model_or = SGQuatd::fromYawPitchRollDeg(
         globals->get_aircraft_model()->get3DModel()->getHeadingDeg(),
         globals->get_aircraft_model()->get3DModel()->getPitchDeg(),
diff --git a/src/Main/viewer.hxx b/src/Main/viewer.hxx
index 455f8f1fd..50d567439 100644
--- a/src/Main/viewer.hxx
+++ b/src/Main/viewer.hxx
@@ -103,13 +103,9 @@ public:
     //   pilot view, model in model view).
     //   FIXME: the model view position (ie target positions) 
     //   should be in the model class.
-    virtual double getLongitude_deg () const { return _position.getLongitudeDeg(); }
-    virtual double getLatitude_deg () const { return _position.getLatitudeDeg(); }
- 
     virtual void setPosition (double lon_deg, double lat_deg, double alt_ft);
     const SGGeod& getPosition() const { return _position; }
 
-
     // Reference geodetic target position...
     virtual void setTargetPosition (double lon_deg, double lat_deg, double alt_ft);
     const SGGeod& getTargetPosition() const { return _target; }
diff --git a/src/Sound/fg_fx.cxx b/src/Sound/fg_fx.cxx
index eb7abd1eb..1774b3a63 100644
--- a/src/Sound/fg_fx.cxx
+++ b/src/Sound/fg_fx.cxx
@@ -226,9 +226,8 @@ FGFX::update_pos_and_orientation(SGSoundMgr *smgr, double dt)
 
     // get the orientation
     const SGQuatd view_or = observer->getViewOrientation();
-    SGQuatd surf_or = SGQuatd::fromLonLatDeg(
-                                observer->getLongitude_deg(),
-                                observer->getLatitude_deg());
+    SGQuatd surf_or = SGQuatd::fromLonLat(observer->getPosition());
+    
     SGQuatd model_or = SGQuatd::fromYawPitchRollDeg(
                                 model->getHeadingDeg(),
                                 model->getPitchDeg(),