source: josm/trunk/src/org/openstreetmap/josm/data/coor/LatLon.java@ 6500

Last change on this file since 6500 was 6500, checked in by simon04, 10 years ago

Add Javadoc for LatLon, add unit tests for LatLonDialog (parsing)
  • Property svn:eol-style set to native
File size: 14.3 KB
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1// License: GPL. For details, see LICENSE file.
2package org.openstreetmap.josm.data.coor;
3
4import static java.lang.Math.PI;
5import static java.lang.Math.asin;
6import static java.lang.Math.atan2;
7import static java.lang.Math.cos;
8import static java.lang.Math.sin;
9import static java.lang.Math.sqrt;
10import static java.lang.Math.toRadians;
11import static org.openstreetmap.josm.tools.I18n.trc;
12
13import java.awt.geom.Area;
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 * <br>
24 * <b>Latitude</b> specifies the north-south position in degrees
25 * where valid values are in the [-90,90] and positive values specify positions north of the equator.
26 * <br>
27 * <b>Longitude</b> specifies the east-west position in degrees
28 * where valid values are in the [-180,180] and positive values specify positions east of the prime meridian.
29 * <br>
30 * <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/6/62/Latitude_and_Longitude_of_the_Earth.svg/500px-Latitude_and_Longitude_of_the_Earth.svg.png">
31 * <br>
32 * This class is immutable.
33 *
34 * @author Imi
35 */
36public class LatLon extends Coordinate {
37
38 /**
39 * Minimum difference in location to not be represented as the same position.
40 * The API returns 7 decimals.
41 */
42 public static final double MAX_SERVER_PRECISION = 1e-7;
43 public static final double MAX_SERVER_INV_PRECISION = 1e7;
44 public static final int MAX_SERVER_DIGITS = 7;
45
46 /**
47 * The (0,0) coordinates.
48 * @since 6178
49 */
50 public static final LatLon ZERO = new LatLon(0, 0);
51
52 private static DecimalFormat cDmsMinuteFormatter = new DecimalFormat("00");
53 private static DecimalFormat cDmsSecondFormatter = new DecimalFormat("00.0");
54 private static DecimalFormat cDmMinuteFormatter = new DecimalFormat("00.000");
55 public static final DecimalFormat cDdFormatter;
56 static {
57 // Don't use the localized decimal separator. This way we can present
58 // a comma separated list of coordinates.
59 cDdFormatter = (DecimalFormat) NumberFormat.getInstance(Locale.UK);
60 cDdFormatter.applyPattern("###0.0######");
61 }
62
63 private static final String cDms60 = cDmsSecondFormatter.format(60.0);
64 private static final String cDms00 = cDmsSecondFormatter.format( 0.0);
65 private static final String cDm60 = cDmMinuteFormatter.format(60.0);
66 private static final String cDm00 = cDmMinuteFormatter.format( 0.0);
67
68 /**
69 * Replies true if lat is in the range [-90,90]
70 *
71 * @param lat the latitude
72 * @return true if lat is in the range [-90,90]
73 */
74 public static boolean isValidLat(double lat) {
75 return lat >= -90d && lat <= 90d;
76 }
77
78 /**
79 * Replies true if lon is in the range [-180,180]
80 *
81 * @param lon the longitude
82 * @return true if lon is in the range [-180,180]
83 */
84 public static boolean isValidLon(double lon) {
85 return lon >= -180d && lon <= 180d;
86 }
87
88 /**
89 * Replies true if lat is in the range [-90,90] and lon is in the range [-180,180]
90 *
91 * @return true if lat is in the range [-90,90] and lon is in the range [-180,180]
92 */
93 public boolean isValid() {
94 return isValidLat(lat()) && isValidLon(lon());
95 }
96
97 public static double toIntervalLat(double value) {
98 if (value < -90)
99 return -90;
100 if (value > 90)
101 return 90;
102 return value;
103 }
104
105 /**
106 * Returns a valid OSM longitude [-180,+180] for the given extended longitude value.
107 * For example, a value of -181 will return +179, a value of +181 will return -179.
108 * @param value A longitude value not restricted to the [-180,+180] range.
109 */
110 public static double toIntervalLon(double value) {
111 if (isValidLon(value))
112 return value;
113 else {
114 int n = (int) (value + Math.signum(value)*180.0) / 360;
115 return value - n*360.0;
116 }
117 }
118
119 /**
120 * Replies the coordinate in degrees/minutes/seconds format
121 * @param pCoordinate The coordinate to convert
122 * @return The coordinate in degrees/minutes/seconds format
123 */
124 public static String dms(double pCoordinate) {
125
126 double tAbsCoord = Math.abs(pCoordinate);
127 int tDegree = (int) tAbsCoord;
128 double tTmpMinutes = (tAbsCoord - tDegree) * 60;
129 int tMinutes = (int) tTmpMinutes;
130 double tSeconds = (tTmpMinutes - tMinutes) * 60;
131
132 String sDegrees = Integer.toString(tDegree);
133 String sMinutes = cDmsMinuteFormatter.format(tMinutes);
134 String sSeconds = cDmsSecondFormatter.format(tSeconds);
135
136 if (sSeconds.equals(cDms60)) {
137 sSeconds = cDms00;
138 sMinutes = cDmsMinuteFormatter.format(tMinutes+1);
139 }
140 if (sMinutes.equals("60")) {
141 sMinutes = "00";
142 sDegrees = Integer.toString(tDegree+1);
143 }
144
145 return sDegrees + "\u00B0" + sMinutes + "\'" + sSeconds + "\"";
146 }
147
148 /**
149 * Replies the coordinate in degrees/minutes format
150 * @param pCoordinate The coordinate to convert
151 * @return The coordinate in degrees/minutes format
152 */
153 public static String dm(double pCoordinate) {
154
155 double tAbsCoord = Math.abs(pCoordinate);
156 int tDegree = (int) tAbsCoord;
157 double tMinutes = (tAbsCoord - tDegree) * 60;
158
159 String sDegrees = Integer.toString(tDegree);
160 String sMinutes = cDmMinuteFormatter.format(tMinutes);
161
162 if (sMinutes.equals(cDm60)) {
163 sMinutes = cDm00;
164 sDegrees = Integer.toString(tDegree+1);
165 }
166
167 return sDegrees + "\u00B0" + sMinutes + "\'";
168 }
169
170 /**
171 * Constructs a new {@link LatLon}
172 * @param lat the latitude, i.e., the north-south position in degrees
173 * @param lon the longitude, i.e., the east-west position in degrees
174 */
175 public LatLon(double lat, double lon) {
176 super(lon, lat);
177 }
178
179 protected LatLon(LatLon coor) {
180 super(coor.lon(), coor.lat());
181 }
182
183 /**
184 * Returns the latitude, i.e., the north-south position in degrees.
185 * @return the latitude
186 */
187 public double lat() {
188 return y;
189 }
190
191 public final static String SOUTH = trc("compass", "S");
192 public final static String NORTH = trc("compass", "N");
193 public String latToString(CoordinateFormat d) {
194 switch(d) {
195 case DECIMAL_DEGREES: return cDdFormatter.format(y);
196 case DEGREES_MINUTES_SECONDS: return dms(y) + ((y < 0) ? SOUTH : NORTH);
197 case NAUTICAL: return dm(y) + ((y < 0) ? SOUTH : NORTH);
198 case EAST_NORTH: return cDdFormatter.format(Main.getProjection().latlon2eastNorth(this).north());
199 default: return "ERR";
200 }
201 }
202
203 /**
204 * Returns the longitude, i.e., the east-west position in degrees.
205 * @return the longitude
206 */
207 public double lon() {
208 return x;
209 }
210
211 public final static String WEST = trc("compass", "W");
212 public final static String EAST = trc("compass", "E");
213 public String lonToString(CoordinateFormat d) {
214 switch(d) {
215 case DECIMAL_DEGREES: return cDdFormatter.format(x);
216 case DEGREES_MINUTES_SECONDS: return dms(x) + ((x < 0) ? WEST : EAST);
217 case NAUTICAL: return dm(x) + ((x < 0) ? WEST : EAST);
218 case EAST_NORTH: return cDdFormatter.format(Main.getProjection().latlon2eastNorth(this).east());
219 default: return "ERR";
220 }
221 }
222
223 /**
224 * @return <code>true</code> if the other point has almost the same lat/lon
225 * values, only differing by no more than
226 * 1 / {@link #MAX_SERVER_PRECISION MAX_SERVER_PRECISION}.
227 */
228 public boolean equalsEpsilon(LatLon other) {
229 double p = MAX_SERVER_PRECISION / 2;
230 return Math.abs(lat()-other.lat()) <= p && Math.abs(lon()-other.lon()) <= p;
231 }
232
233 /**
234 * @return <code>true</code>, if the coordinate is outside the world, compared
235 * by using lat/lon.
236 */
237 public boolean isOutSideWorld() {
238 Bounds b = Main.getProjection().getWorldBoundsLatLon();
239 return lat() < b.getMinLat() || lat() > b.getMaxLat() ||
240 lon() < b.getMinLon() || lon() > b.getMaxLon();
241 }
242
243 /**
244 * @return <code>true</code> if this is within the given bounding box.
245 */
246 public boolean isWithin(Bounds b) {
247 return b.contains(this);
248 }
249
250 /**
251 * Check if this is contained in given area or area is null.
252 *
253 * @param a Area
254 * @return <code>true</code> if this is contained in given area or area is null.
255 */
256 public boolean isIn(Area a) {
257 return a == null || a.contains(x, y);
258 }
259
260 /**
261 * Computes the distance between this lat/lon and another point on the earth.
262 * Uses Haversine formular.
263 * @param other the other point.
264 * @return distance in metres.
265 */
266 public double greatCircleDistance(LatLon other) {
267 double R = 6378135;
268 double sinHalfLat = sin(toRadians(other.lat() - this.lat()) / 2);
269 double sinHalfLon = sin(toRadians(other.lon() - this.lon()) / 2);
270 double d = 2 * R * asin(
271 sqrt(sinHalfLat*sinHalfLat +
272 cos(toRadians(this.lat()))*cos(toRadians(other.lat()))*sinHalfLon*sinHalfLon));
273 // For points opposite to each other on the sphere,
274 // rounding errors could make the argument of asin greater than 1
275 // (This should almost never happen.)
276 if (java.lang.Double.isNaN(d)) {
277 Main.error("NaN in greatCircleDistance");
278 d = PI * R;
279 }
280 return d;
281 }
282
283 /**
284 * Returns the heading, in radians, that you have to use to get from
285 * this lat/lon to another.
286 *
287 * (I don't know the original source of this formula, but see
288 * http://math.stackexchange.com/questions/720/how-to-calculate-a-heading-on-the-earths-surface
289 * for some hints how it is derived.)
290 *
291 * @param other the "destination" position
292 * @return heading in the range 0 <= hd < 2*PI
293 */
294 public double heading(LatLon other) {
295 double hd = atan2(sin(toRadians(this.lon() - other.lon())) * cos(toRadians(other.lat())),
296 cos(toRadians(this.lat())) * sin(toRadians(other.lat())) -
297 sin(toRadians(this.lat())) * cos(toRadians(other.lat())) * cos(toRadians(this.lon() - other.lon())));
298 hd %= 2 * PI;
299 if (hd < 0) {
300 hd += 2 * PI;
301 }
302 return hd;
303 }
304
305 /**
306 * Returns this lat/lon pair in human-readable format.
307 *
308 * @return String in the format "lat=1.23456 deg, lon=2.34567 deg"
309 */
310 public String toDisplayString() {
311 NumberFormat nf = NumberFormat.getInstance();
312 nf.setMaximumFractionDigits(5);
313 return "lat=" + nf.format(lat()) + "\u00B0, lon=" + nf.format(lon()) + "\u00B0";
314 }
315
316 public LatLon interpolate(LatLon ll2, double proportion) {
317 return new LatLon(this.lat() + proportion * (ll2.lat() - this.lat()),
318 this.lon() + proportion * (ll2.lon() - this.lon()));
319 }
320
321 public LatLon getCenter(LatLon ll2) {
322 return new LatLon((this.lat() + ll2.lat())/2.0, (this.lon() + ll2.lon())/2.0);
323 }
324
325 /**
326 * Returns the euclidean distance from this {@code LatLon} to a specified {@code LatLon}.
327 *
328 * @param ll the specified coordinate to be measured against this {@code LatLon}
329 * @return the euclidean distance from this {@code LatLon} to a specified {@code LatLon}
330 * @since 6166
331 */
332 public double distance(final LatLon ll) {
333 return super.distance(ll);
334 }
335
336 /**
337 * Returns the square of the euclidean distance from this {@code LatLon} to a specified {@code LatLon}.
338 *
339 * @param ll the specified coordinate to be measured against this {@code LatLon}
340 * @return the square of the euclidean distance from this {@code LatLon} to a specified {@code LatLon}
341 * @since 6166
342 */
343 public double distanceSq(final LatLon ll) {
344 return super.distanceSq(ll);
345 }
346
347 @Override public String toString() {
348 return "LatLon[lat="+lat()+",lon="+lon()+"]";
349 }
350
351 /**
352 * Returns the value rounded to OSM precisions, i.e. to
353 * LatLon.MAX_SERVER_PRECISION
354 *
355 * @return rounded value
356 */
357 public static double roundToOsmPrecision(double value) {
358 return Math.round(value * MAX_SERVER_INV_PRECISION) / MAX_SERVER_INV_PRECISION;
359 }
360
361 /**
362 * Returns the value rounded to OSM precision. This function is now the same as
363 * {@link #roundToOsmPrecision(double)}, since the rounding error has been fixed.
364 *
365 * @return rounded value
366 */
367 public static double roundToOsmPrecisionStrict(double value) {
368 return roundToOsmPrecision(value);
369 }
370
371 /**
372 * Replies a clone of this lat LatLon, rounded to OSM precisions, i.e. to
373 * MAX_SERVER_PRECISION
374 *
375 * @return a clone of this lat LatLon
376 */
377 public LatLon getRoundedToOsmPrecision() {
378 return new LatLon(
379 roundToOsmPrecision(lat()),
380 roundToOsmPrecision(lon())
381 );
382 }
383
384 /**
385 * Replies a clone of this lat LatLon, rounded to OSM precisions, i.e. to
386 * MAX_SERVER_PRECISION
387 *
388 * @return a clone of this lat LatLon
389 */
390 public LatLon getRoundedToOsmPrecisionStrict() {
391 return new LatLon(
392 roundToOsmPrecisionStrict(lat()),
393 roundToOsmPrecisionStrict(lon())
394 );
395 }
396
397 @Override
398 public int hashCode() {
399 final int prime = 31;
400 int result = super.hashCode();
401 long temp;
402 temp = java.lang.Double.doubleToLongBits(x);
403 result = prime * result + (int) (temp ^ (temp >>> 32));
404 temp = java.lang.Double.doubleToLongBits(y);
405 result = prime * result + (int) (temp ^ (temp >>> 32));
406 return result;
407 }
408
409 @Override
410 public boolean equals(Object obj) {
411 if (this == obj)
412 return true;
413 if (!super.equals(obj))
414 return false;
415 if (getClass() != obj.getClass())
416 return false;
417 Coordinate other = (Coordinate) obj;
418 if (java.lang.Double.doubleToLongBits(x) != java.lang.Double.doubleToLongBits(other.x))
419 return false;
420 if (java.lang.Double.doubleToLongBits(y) != java.lang.Double.doubleToLongBits(other.y))
421 return false;
422 return true;
423 }
424}
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