gov/nasa/worldwind/geom/LatLon.java

   1 /*
   2 Copyright (C) 2001, 2006 United States Government
   3 as represented by the Administrator of the
   4 National Aeronautics and Space Administration.
   5 All Rights Reserved.
   6 */
   7 package gov.nasa.worldwind.geom;
   8
   9 import gov.nasa.worldwind.*;
  10
  11 /**
  12  * Represents a point on the two-dimensional surface of a globe. Latitude is the degrees North and ranges between [-90,
  13  * 90], while longitude refers to degrees East, and ranges between (-180, 180].
  14  * <p/>
  15  * Instances of <code>LatLon</code> are immutable.
  16  *
  17  * @author Tom Gaskins
  18  * @version $Id: LatLon.java 1749 2007-05-06 19:48:14Z tgaskins $
  19  */
  20 public class LatLon
  21 {
  22     private final Angle latitude;
  23     private final Angle longitude;
  24
  25     /**
  26      * Factor method for obtaining a new <code>LatLon</code> from two angles expressed in radians.
  27      *
  28      * @param latitude  in radians
  29      * @param longitude in radians
  30      * @return a new <code>LatLon</code> from the given angles, which are expressed as radians
  31      */
  32     public static LatLon fromRadians(double latitude, double longitude)
  33     {
  34         return new LatLon(Math.toDegrees(latitude), Math.toDegrees(longitude));
  35     }
  36
  37     /**
  38      * Factory method for obtaining a new <code>LatLon</code> from two angles expressed in degrees.
  39      *
  40      * @param latitude  in degrees
  41      * @param longitude in degrees
  42      * @return a new <code>LatLon</code> from the given angles, which are expressed as degrees
  43      */
  44     public static LatLon fromDegrees(double latitude, double longitude)
  45     {
  46         return new LatLon(latitude, longitude);
  47     }
  48
  49     private LatLon(double latitude, double longitude)
  50     {
  51         this.latitude = Angle.fromDegrees(latitude);
  52         this.longitude = Angle.fromDegrees(longitude);
  53     }
  54
  55     /**
  56      * Contructs a new  <code>LatLon</code> from two angles. Neither angle may be null.
  57      *
  58      * @param latitude
  59      * @param longitude
  60      * @throws IllegalArgumentException if <code>latitude</code> or <code>longitude</code> is null
  61      */
  62     public LatLon(Angle latitude, Angle longitude)
  63     {
  64         if (latitude == null || longitude == null)
  65         {
  66             String message = WorldWind.retrieveErrMsg("nullValue.LatitudeOrLongitudeIsNull");
  67             WorldWind.logger().log(java.util.logging.Level.FINE, message);
  68             throw new IllegalArgumentException(message);
  69         }
  70
  71         this.latitude = latitude;
  72         this.longitude = longitude;
  73     }
  74
  75     /**
  76      * Obtains the latitude of this <code>LatLon</code>.
  77      *
  78      * @return this <code>LatLon</code>'s latitude
  79      */
  80     public final Angle getLatitude()
  81     {
  82         return this.latitude;
  83     }
  84
  85     /**
  86      * Obtains the longitude of this <code>LatLon</code>.
  87      *
  88      * @return this <code>LatLon</code>'s longitude
  89      */
  90     public final Angle getLongitude()
  91     {
  92         return this.longitude;
  93     }
  94
  95     public static LatLon interpolate(double t, LatLon begin, LatLon end)
  96     {
  97         if (begin == null || end == null)
  98         {
  99             String message = WorldWind.retrieveErrMsg("nullValue.LatitudeOrLongitudeIsNull");
 100             WorldWind.logger().log(java.util.logging.Level.FINE, message);
 101             throw new IllegalArgumentException(message);
 102         }
 103
 104         if (t < 0)
 105             return begin;
 106         else if (t > 1)
 107             return end;
 108         Quaternion beginQuat = Quaternion.EulerToQuaternion(begin.getLongitude().getRadians(),
 109             begin.getLatitude().getRadians(), 0);
 110         Quaternion endQuat = Quaternion.EulerToQuaternion(end.getLongitude().getRadians(),
 111             end.getLatitude().getRadians(), 0);
 112         Quaternion q = Quaternion.Slerp(beginQuat, endQuat, t);
 113         Point v = Quaternion.QuaternionToEuler(q);
 114         if (Double.isNaN(v.x()) || Double.isNaN(v.y()))
 115             return null;
 116         return LatLon.fromRadians(v.y(), v.x());
 117     }
 118
 119     @Override
 120     public String toString()
 121     {
 122         return "(" + this.latitude.toString() + ", " + this.longitude.toString() + ")";
 123     }
 124
 125     @Override
 126     public boolean equals(Object o)
 127     {
 128         if (this == o)
 129             return true;
 130         if (o == null || getClass() != o.getClass())
 131             return false;
 132
 133         final gov.nasa.worldwind.geom.LatLon latLon = (gov.nasa.worldwind.geom.LatLon) o;
 134
 135         if (!latitude.equals(latLon.latitude))
 136             return false;
 137         //noinspection RedundantIfStatement
 138         if (!longitude.equals(latLon.longitude))
 139             return false;
 140
 141         return true;
 142     }
 143
 144     @Override
 145     public int hashCode()
 146     {
 147         int result;
 148         result = latitude.hashCode();
 149         result = 29 * result + longitude.hashCode();
 150         return result;
 151     }
 152 }