menu icons, window sizing, compass direction selector

[debian/openrocket] / src / net / sf / openrocket / util / GeodeticComputationStrategy.java

diff --git a/src/net/sf/openrocket/util/GeodeticComputationStrategy.java b/src/net/sf/openrocket/util/GeodeticComputationStrategy.java
index 8e7d2f29978f9648c549fe24537e0952a3b2e546..6f1fb53aa4dc425d893ebe7c17b6736325069f4a 100644 (file)
--- a/src/net/sf/openrocket/util/GeodeticComputationStrategy.java
+++ b/src/net/sf/openrocket/util/GeodeticComputationStrategy.java
@@ -5,22 +5,41 @@ import net.sf.openrocket.startup.Application;
 
 /**
  * A strategy that performs computations on WorldCoordinates.
+ * <p>
+ * The directions of the coordinate is:
+ *   positive X = EAST
+ *   positive Y = NORTH
+ *   positive Z = UPWARDS
  */
 public enum GeodeticComputationStrategy {
        
 
        /**
-        * Perform no geodetic computations.  The addCoordinate method does nothing and
-        * getCoriolisAcceleration returns Coordinate.NUL.
+        * Perform computations using a flat Earth approximation.  addCoordinate computes the
+        * location using a direct meters-per-degree scaling and getCoriolisAcceleration always
+        * returns NUL.
         */
-       NONE {
+       FLAT {
+               private static final double METERS_PER_DEGREE_LATITUDE = 111325; // "standard figure"
+               private static final double METERS_PER_DEGREE_LONGITUDE_EQUATOR = 111050;
+               
+               
                @Override
-               public WorldCoordinate addCoordinate(WorldCoordinate latlon, Coordinate delta) {
-                       return latlon;
+               public WorldCoordinate addCoordinate(WorldCoordinate location, Coordinate delta) {
+                       
+                       double metersPerDegreeLongitude = METERS_PER_DEGREE_LONGITUDE_EQUATOR * Math.cos(location.getLatitudeRad());
+                       // Limit to 1 meter per degree near poles
+                       metersPerDegreeLongitude = MathUtil.max(metersPerDegreeLongitude, 1);
+                       
+                       double newLat = location.getLatitudeDeg() + delta.y / METERS_PER_DEGREE_LATITUDE;
+                       double newLon = location.getLongitudeDeg() + delta.x / metersPerDegreeLongitude;
+                       double newAlt = location.getAltitude() + delta.z;
+                       
+                       return new WorldCoordinate(newLat, newLon, newAlt);
                }
                
                @Override
-               public Coordinate getCoriolisAcceleration(WorldCoordinate latlon, Coordinate velocity) {
+               public Coordinate getCoriolisAcceleration(WorldCoordinate location, Coordinate velocity) {
                        return Coordinate.NUL;
                }
        },
@@ -37,9 +56,13 @@ public enum GeodeticComputationStrategy {
                        // bearing (in radians, clockwise from north);
                        // d/R is the angular distance (in radians), where d is the distance traveled and R is the earth’s radius
                        double d = MathUtil.hypot(delta.x, delta.y);
-                       double bearing = Math.atan(delta.x / delta.y);
-                       if (delta.y < 0)
-                               bearing = bearing + Math.PI;
+                       
+                       // Check for zero movement before computing bearing
+                       if (MathUtil.equals(d, 0)) {
+                               return new WorldCoordinate(location.getLatitudeDeg(), location.getLongitudeDeg(), newAlt);
+                       }
+                       
+                       double bearing = Math.atan2(delta.x, delta.y);
                        
                        // Calculate the new lat and lon                
                        double newLat, newLon;
@@ -51,20 +74,17 @@ public enum GeodeticComputationStrategy {
                        newLat = Math.asin(sinLat * cosDR + cosLat * sinDR * Math.cos(bearing));
                        newLon = location.getLongitudeRad() + Math.atan2(Math.sin(bearing) * sinDR * cosLat, cosDR - sinLat * Math.sin(newLat));
                        
-                       if (Double.isNaN(newLat)) {
-                               newLat = location.getLatitudeRad();
-                       }
-                       
-                       if (Double.isNaN(newLon)) {
-                               newLon = location.getLongitudeRad();
+                       if (Double.isNaN(newLat) || Double.isNaN(newLon)) {
+                               throw new BugException("addCoordinate resulted in NaN location:  location=" + location + " delta=" + delta
+                                               + " newLat=" + newLat + " newLon=" + newLon);
                        }
                        
                        return new WorldCoordinate(Math.toDegrees(newLat), Math.toDegrees(newLon), newAlt);
                }
                
                @Override
-               public Coordinate getCoriolisAcceleration(WorldCoordinate latlon, Coordinate velocity) {
-                       return computeCoriolisAcceleration(latlon, velocity);
+               public Coordinate getCoriolisAcceleration(WorldCoordinate location, Coordinate velocity) {
+                       return computeCoriolisAcceleration(location, velocity);
                }
                
        },
@@ -81,6 +101,12 @@ public enum GeodeticComputationStrategy {
                        // bearing (in radians, clockwise from north);
                        // d/R is the angular distance (in radians), where d is the distance traveled and R is the earth’s radius
                        double d = MathUtil.hypot(delta.x, delta.y);
+                       
+                       // Check for zero movement before computing bearing
+                       if (MathUtil.equals(d, 0)) {
+                               return new WorldCoordinate(location.getLatitudeDeg(), location.getLongitudeDeg(), newAlt);
+                       }
+                       
                        double bearing = Math.atan(delta.x / delta.y);
                        if (delta.y < 0)
                                bearing = bearing + Math.PI;
@@ -91,19 +117,17 @@ public enum GeodeticComputationStrategy {
                        newLat = ret[0];
                        newLon = ret[1];
                        
-                       if (Double.isNaN(newLat)) {
-                               newLat = location.getLatitudeRad();
+                       if (Double.isNaN(newLat) || Double.isNaN(newLon)) {
+                               throw new BugException("addCoordinate resulted in NaN location:  location=" + location + " delta=" + delta
+                                               + " newLat=" + newLat + " newLon=" + newLon);
                        }
                        
-                       if (Double.isNaN(newLon)) {
-                               newLon = location.getLongitudeRad();
-                       }
-                       return new WorldCoordinate(newLat, newLon, newAlt);
+                       return new WorldCoordinate(Math.toDegrees(newLat), Math.toDegrees(newLon), newAlt);
                }
                
                @Override
-               public Coordinate getCoriolisAcceleration(WorldCoordinate latlon, Coordinate velocity) {
-                       return computeCoriolisAcceleration(latlon, velocity);
+               public Coordinate getCoriolisAcceleration(WorldCoordinate location, Coordinate velocity) {
+                       return computeCoriolisAcceleration(location, velocity);
                }
        };
        
@@ -136,13 +160,13 @@ public enum GeodeticComputationStrategy {
        /**
         * Add a cartesian movement coordinate to a WorldCoordinate.
         */
-       public abstract WorldCoordinate addCoordinate(WorldCoordinate latlon, Coordinate delta);
+       public abstract WorldCoordinate addCoordinate(WorldCoordinate location, Coordinate delta);
        
        
        /**
         * Compute the coriolis acceleration at a specified WorldCoordinate and velocity.
         */
-       public abstract Coordinate getCoriolisAcceleration(WorldCoordinate latlon, Coordinate velocity);
+       public abstract Coordinate getCoriolisAcceleration(WorldCoordinate location, Coordinate velocity);