source: josm/trunk/src/org/openstreetmap/josm/data/coor/LatLon.java@ 4234

Last change on this file since 4234 was 4206, checked in by bastiK, 13 years ago

change heading formula to something sane
  • Property svn:eol-style set to native
File size: 9.0 KB
Line 
1// License: GPL. Copyright 2007 by Immanuel Scholz and others
2package org.openstreetmap.josm.data.coor;
3
4import static org.openstreetmap.josm.tools.I18n.trc;
5
6import static java.lang.Math.PI;
7import static java.lang.Math.asin;
8import static java.lang.Math.atan2;
9import static java.lang.Math.cos;
10import static java.lang.Math.sin;
11import static java.lang.Math.sqrt;
12import static java.lang.Math.toRadians;
13
14import java.text.DecimalFormat;
15import java.text.NumberFormat;
16import java.util.Locale;
17
18import org.openstreetmap.josm.Main;
19import org.openstreetmap.josm.data.Bounds;
20
21/**
22 * LatLon are unprojected latitude / longitude coordinates.
23 *
24 * This class is immutable.
25 *
26 * @author Imi
27 */
28public class LatLon extends Coordinate {
29
30 /**
31 * Minimum difference in location to not be represented as the same position.
32 * The API returns 7 decimals.
33 */
34 public static final double MAX_SERVER_PRECISION = 1e-7;
35
36 private static DecimalFormat cDmsMinuteFormatter = new DecimalFormat("00");
37 private static DecimalFormat cDmsSecondFormatter = new DecimalFormat("00.0");
38 private static DecimalFormat cDmMinuteFormatter = new DecimalFormat("00.000");
39 public static DecimalFormat cDdFormatter;
40 static {
41 // Don't use the localized decimal separator. This way we can present
42 // a comma separated list of coordinates.
43 cDdFormatter = (DecimalFormat) NumberFormat.getInstance(Locale.UK);
44 cDdFormatter.applyPattern("###0.0000000");
45 }
46
47 /**
48 * Replies true if lat is in the range [-90,90]
49 *
50 * @param lat the latitude
51 * @return true if lat is in the range [-90,90]
52 */
53 public static boolean isValidLat(double lat) {
54 return lat >= -90d && lat <= 90d;
55 }
56
57 /**
58 * Replies true if lon is in the range [-180,180]
59 *
60 * @param lon the longitude
61 * @return true if lon is in the range [-180,180]
62 */
63 public static boolean isValidLon(double lon) {
64 return lon >= -180d && lon <= 180d;
65 }
66
67 /**
68 * Replies the coordinate in degrees/minutes/seconds format
69 */
70 public static String dms(double pCoordinate) {
71
72 double tAbsCoord = Math.abs(pCoordinate);
73 int tDegree = (int) tAbsCoord;
74 double tTmpMinutes = (tAbsCoord - tDegree) * 60;
75 int tMinutes = (int) tTmpMinutes;
76 double tSeconds = (tTmpMinutes - tMinutes) * 60;
77
78 return tDegree + "\u00B0" + cDmsMinuteFormatter.format(tMinutes) + "\'"
79 + cDmsSecondFormatter.format(tSeconds) + "\"";
80 }
81
82 public static String dm(double pCoordinate) {
83
84 double tAbsCoord = Math.abs(pCoordinate);
85 int tDegree = (int) tAbsCoord;
86 double tMinutes = (tAbsCoord - tDegree) * 60;
87 return tDegree + "\u00B0" + cDmMinuteFormatter.format(tMinutes) + "\'";
88 }
89
90 public LatLon(double lat, double lon) {
91 super(lon, lat);
92 }
93
94 public LatLon(LatLon coor) {
95 super(coor.lon(), coor.lat());
96 }
97
98 public double lat() {
99 return y;
100 }
101
102 public final static String SOUTH = trc("compass", "S");
103 public final static String NORTH = trc("compass", "N");
104 public String latToString(CoordinateFormat d) {
105 switch(d) {
106 case DECIMAL_DEGREES: return cDdFormatter.format(y);
107 case DEGREES_MINUTES_SECONDS: return dms(y) + ((y < 0) ? SOUTH : NORTH);
108 case NAUTICAL: return dm(y) + ((y < 0) ? SOUTH : NORTH);
109 case EAST_NORTH: return cDdFormatter.format(Main.getProjection().latlon2eastNorth(this).north());
110 default: return "ERR";
111 }
112 }
113
114 public double lon() {
115 return x;
116 }
117
118 public final static String WEST = trc("compass", "W");
119 public final static String EAST = trc("compass", "E");
120 public String lonToString(CoordinateFormat d) {
121 switch(d) {
122 case DECIMAL_DEGREES: return cDdFormatter.format(x);
123 case DEGREES_MINUTES_SECONDS: return dms(x) + ((x < 0) ? WEST : EAST);
124 case NAUTICAL: return dm(x) + ((x < 0) ? WEST : EAST);
125 case EAST_NORTH: return cDdFormatter.format(Main.getProjection().latlon2eastNorth(this).east());
126 default: return "ERR";
127 }
128 }
129
130 /**
131 * @return <code>true</code> if the other point has almost the same lat/lon
132 * values, only differing by no more than
133 * 1 / {@link #MAX_SERVER_PRECISION MAX_SERVER_PRECISION}.
134 */
135 public boolean equalsEpsilon(LatLon other) {
136 double p = MAX_SERVER_PRECISION / 2;
137 return Math.abs(lat()-other.lat()) <= p && Math.abs(lon()-other.lon()) <= p;
138 }
139
140 /**
141 * @return <code>true</code>, if the coordinate is outside the world, compared
142 * by using lat/lon.
143 */
144 public boolean isOutSideWorld() {
145 Bounds b = Main.getProjection().getWorldBoundsLatLon();
146 return lat() < b.getMin().lat() || lat() > b.getMax().lat() ||
147 lon() < b.getMin().lon() || lon() > b.getMax().lon();
148 }
149
150 /**
151 * @return <code>true</code> if this is within the given bounding box.
152 */
153 public boolean isWithin(Bounds b) {
154 return lat() >= b.getMin().lat() && lat() <= b.getMax().lat() && lon() > b.getMin().lon() && lon() < b.getMax().lon();
155 }
156
157 /**
158 * Computes the distance between this lat/lon and another point on the earth.
159 * Uses Haversine formular.
160 * @param other the other point.
161 * @return distance in metres.
162 */
163 public double greatCircleDistance(LatLon other) {
164 double R = 6378135;
165 double sinHalfLat = sin(toRadians(other.lat() - this.lat()) / 2);
166 double sinHalfLon = sin(toRadians(other.lon() - this.lon()) / 2);
167 double d = 2 * R * asin(
168 sqrt(sinHalfLat*sinHalfLat +
169 cos(toRadians(this.lat()))*cos(toRadians(other.lat()))*sinHalfLon*sinHalfLon));
170 // For points opposite to each other on the sphere,
171 // rounding errors could make the argument of asin greater than 1
172 // (This should almost never happen.)
173 if (java.lang.Double.isNaN(d)) {
174 System.err.println("Error: NaN in greatCircleDistance");
175 d = PI * R;
176 }
177 return d;
178 }
179
180 /**
181 * Returns the heading, in radians, that you have to use to get from
182 * this lat/lon to another.
183 *
184 * (I don't know the original source of this formula, but see
185 * http://math.stackexchange.com/questions/720/how-to-calculate-a-heading-on-the-earths-surface
186 * for some hints how it is derived.)
187 *
188 * @param other the "destination" position
189 * @return heading in the range 0 <= hd < 2*PI
190 */
191 public double heading(LatLon other) {
192 double hd = atan2(sin(toRadians(this.lon() - other.lon())) * cos(toRadians(other.lat())),
193 cos(toRadians(this.lat())) * sin(toRadians(other.lat())) -
194 sin(toRadians(this.lat())) * cos(toRadians(other.lat())) * cos(toRadians(this.lon() - other.lon())));
195 hd %= 2 * PI;
196 if (hd < 0) {
197 hd += 2 * PI;
198 }
199 return hd;
200 }
201
202 /**
203 * Returns this lat/lon pair in human-readable format.
204 *
205 * @return String in the format "lat=1.23456 deg, lon=2.34567 deg"
206 */
207 public String toDisplayString() {
208 NumberFormat nf = NumberFormat.getInstance();
209 nf.setMaximumFractionDigits(5);
210 return "lat=" + nf.format(lat()) + "\u00B0, lon=" + nf.format(lon()) + "\u00B0";
211 }
212
213 public LatLon interpolate(LatLon ll2, double proportion) {
214 return new LatLon(this.lat() + proportion * (ll2.lat() - this.lat()),
215 this.lon() + proportion * (ll2.lon() - this.lon()));
216 }
217
218 public LatLon getCenter(LatLon ll2) {
219 return new LatLon((this.lat() + ll2.lat())/2.0, (this.lon() + ll2.lon())/2.0);
220 }
221
222 @Override public String toString() {
223 return "LatLon[lat="+lat()+",lon="+lon()+"]";
224 }
225
226 /**
227 * Replies a clone of this lat LatLon, rounded to OSM precisions, i.e. to
228 * MAX_SERVER_PRECISION
229 *
230 * @return a clone of this lat LatLon
231 */
232 public LatLon getRoundedToOsmPrecision() {
233 return new LatLon(
234 Math.round(lat() / MAX_SERVER_PRECISION) * MAX_SERVER_PRECISION,
235 Math.round(lon() / MAX_SERVER_PRECISION) * MAX_SERVER_PRECISION
236 );
237 }
238
239 @Override
240 public int hashCode() {
241 final int prime = 31;
242 int result = super.hashCode();
243 long temp;
244 temp = java.lang.Double.doubleToLongBits(x);
245 result = prime * result + (int) (temp ^ (temp >>> 32));
246 temp = java.lang.Double.doubleToLongBits(y);
247 result = prime * result + (int) (temp ^ (temp >>> 32));
248 return result;
249 }
250
251 @Override
252 public boolean equals(Object obj) {
253 if (this == obj)
254 return true;
255 if (!super.equals(obj))
256 return false;
257 if (getClass() != obj.getClass())
258 return false;
259 Coordinate other = (Coordinate) obj;
260 if (java.lang.Double.doubleToLongBits(x) != java.lang.Double.doubleToLongBits(other.x))
261 return false;
262 if (java.lang.Double.doubleToLongBits(y) != java.lang.Double.doubleToLongBits(other.y))
263 return false;
264 return true;
265 }
266}
Note: See TracBrowser for help on using the repository browser.