001    // License: GPL. Copyright 2007 by Immanuel Scholz and others
002    package org.openstreetmap.josm.data.coor;
003    
004    import static java.lang.Math.PI;
005    import static java.lang.Math.asin;
006    import static java.lang.Math.atan2;
007    import static java.lang.Math.cos;
008    import static java.lang.Math.sin;
009    import static java.lang.Math.sqrt;
010    import static java.lang.Math.toRadians;
011    import static org.openstreetmap.josm.tools.I18n.trc;
012    
013    import java.text.DecimalFormat;
014    import java.text.NumberFormat;
015    import java.util.Locale;
016    
017    import org.openstreetmap.josm.Main;
018    import org.openstreetmap.josm.data.Bounds;
019    
020    /**
021     * LatLon are unprojected latitude / longitude coordinates.
022     *
023     * This class is immutable.
024     *
025     * @author Imi
026     */
027    public class LatLon extends Coordinate {
028    
029    
030        /**
031         * Minimum difference in location to not be represented as the same position.
032         * The API returns 7 decimals.
033         */
034        public static final double MAX_SERVER_PRECISION = 1e-7;
035        public static final double MAX_SERVER_INV_PRECISION = 1e7;
036        public static final int    MAX_SERVER_DIGITS = 7;
037    
038        private static DecimalFormat cDmsMinuteFormatter = new DecimalFormat("00");
039        private static DecimalFormat cDmsSecondFormatter = new DecimalFormat("00.0");
040        private static DecimalFormat cDmMinuteFormatter = new DecimalFormat("00.000");
041        public static final DecimalFormat cDdFormatter;
042        static {
043            // Don't use the localized decimal separator. This way we can present
044            // a comma separated list of coordinates.
045            cDdFormatter = (DecimalFormat) NumberFormat.getInstance(Locale.UK);
046            cDdFormatter.applyPattern("###0.0######");
047        }
048    
049        /**
050         * Replies true if lat is in the range [-90,90]
051         *
052         * @param lat the latitude
053         * @return true if lat is in the range [-90,90]
054         */
055        public static boolean isValidLat(double lat) {
056            return lat >= -90d && lat <= 90d;
057        }
058    
059        /**
060         * Replies true if lon is in the range [-180,180]
061         *
062         * @param lon the longitude
063         * @return true if lon is in the range [-180,180]
064         */
065        public static boolean isValidLon(double lon) {
066            return lon >= -180d && lon <= 180d;
067        }
068    
069        /**
070         * Replies true if lat is in the range [-90,90] and lon is in the range [-180,180]
071         *
072         * @return true if lat is in the range [-90,90] and lon is in the range [-180,180]
073         */
074        public boolean isValid() {
075            return isValidLat(lat()) && isValidLon(lon());
076        }
077    
078        public static double toIntervalLat(double value) {
079            if (value < -90)
080                return -90;
081            if (value > 90)
082                return 90;
083            return value;
084        }
085    
086        /**
087         * Returns a valid OSM longitude [-180,+180] for the given extended longitude value.
088         * For example, a value of -181 will return +179, a value of +181 will return -179.
089         * @param lon A longitude value not restricted to the [-180,+180] range.
090         */
091        public static double toIntervalLon(double value) {
092            if (isValidLon(value))
093                return value;
094            else {
095                int n = (int) (value + Math.signum(value)*180.0) / 360;
096                return value - n*360.0;
097            }
098        }
099    
100        /**
101         * Replies the coordinate in degrees/minutes/seconds format
102         * @param pCoordinate The coordinate to convert
103         * @return The coordinate in degrees/minutes/seconds format
104         */
105        public static String dms(double pCoordinate) {
106    
107            double tAbsCoord = Math.abs(pCoordinate);
108            int tDegree = (int) tAbsCoord;
109            double tTmpMinutes = (tAbsCoord - tDegree) * 60;
110            int tMinutes = (int) tTmpMinutes;
111            double tSeconds = (tTmpMinutes - tMinutes) * 60;
112            
113            String sDegrees = Integer.toString(tDegree);
114            String sMinutes = cDmsMinuteFormatter.format(tMinutes);
115            String sSeconds = cDmsSecondFormatter.format(tSeconds);
116            
117            if (sSeconds.equals("60.0")) {
118                sSeconds = "00.0";
119                sMinutes = cDmsMinuteFormatter.format(tMinutes+1);
120            }
121            if (sMinutes.equals("60")) {
122                sMinutes = "00";
123                sDegrees = Integer.toString(tDegree+1);
124            }
125    
126            return sDegrees + "\u00B0" + sMinutes + "\'" + sSeconds + "\"";
127        }
128    
129        /**
130         * Replies the coordinate in degrees/minutes format
131         * @param pCoordinate The coordinate to convert
132         * @return The coordinate in degrees/minutes format
133         */
134        public static String dm(double pCoordinate) {
135    
136            double tAbsCoord = Math.abs(pCoordinate);
137            int tDegree = (int) tAbsCoord;
138            double tMinutes = (tAbsCoord - tDegree) * 60;
139            
140            String sDegrees = Integer.toString(tDegree);
141            String sMinutes = cDmMinuteFormatter.format(tMinutes);
142            
143            if (sMinutes.equals("60.000")) {
144                sMinutes = "00.000";
145                sDegrees = Integer.toString(tDegree+1);
146            }
147            
148            return sDegrees + "\u00B0" + sMinutes + "\'";
149        }
150    
151        public LatLon(double lat, double lon) {
152            super(lon, lat);
153        }
154    
155        public LatLon(LatLon coor) {
156            super(coor.lon(), coor.lat());
157        }
158    
159        public double lat() {
160            return y;
161        }
162    
163        public final static String SOUTH = trc("compass", "S");
164        public final static String NORTH = trc("compass", "N");
165        public String latToString(CoordinateFormat d) {
166            switch(d) {
167            case DECIMAL_DEGREES: return cDdFormatter.format(y);
168            case DEGREES_MINUTES_SECONDS: return dms(y) + ((y < 0) ? SOUTH : NORTH);
169            case NAUTICAL: return dm(y) + ((y < 0) ? SOUTH : NORTH);
170            case EAST_NORTH: return cDdFormatter.format(Main.getProjection().latlon2eastNorth(this).north());
171            default: return "ERR";
172            }
173        }
174    
175        public double lon() {
176            return x;
177        }
178    
179        public final static String WEST = trc("compass", "W");
180        public final static String EAST = trc("compass", "E");
181        public String lonToString(CoordinateFormat d) {
182            switch(d) {
183            case DECIMAL_DEGREES: return cDdFormatter.format(x);
184            case DEGREES_MINUTES_SECONDS: return dms(x) + ((x < 0) ? WEST : EAST);
185            case NAUTICAL: return dm(x) + ((x < 0) ? WEST : EAST);
186            case EAST_NORTH: return cDdFormatter.format(Main.getProjection().latlon2eastNorth(this).east());
187            default: return "ERR";
188            }
189        }
190    
191        /**
192         * @return <code>true</code> if the other point has almost the same lat/lon
193         * values, only differing by no more than
194         * 1 / {@link #MAX_SERVER_PRECISION MAX_SERVER_PRECISION}.
195         */
196        public boolean equalsEpsilon(LatLon other) {
197            double p = MAX_SERVER_PRECISION / 2;
198            return Math.abs(lat()-other.lat()) <= p && Math.abs(lon()-other.lon()) <= p;
199        }
200    
201        /**
202         * @return <code>true</code>, if the coordinate is outside the world, compared
203         * by using lat/lon.
204         */
205        public boolean isOutSideWorld() {
206            Bounds b = Main.getProjection().getWorldBoundsLatLon();
207            return lat() < b.getMin().lat() || lat() > b.getMax().lat() ||
208                    lon() < b.getMin().lon() || lon() > b.getMax().lon();
209        }
210    
211        /**
212         * @return <code>true</code> if this is within the given bounding box.
213         */
214        public boolean isWithin(Bounds b) {
215            return b.contains(this);
216        }
217    
218        /**
219         * Computes the distance between this lat/lon and another point on the earth.
220         * Uses Haversine formular.
221         * @param other the other point.
222         * @return distance in metres.
223         */
224        public double greatCircleDistance(LatLon other) {
225            double R = 6378135;
226            double sinHalfLat = sin(toRadians(other.lat() - this.lat()) / 2);
227            double sinHalfLon = sin(toRadians(other.lon() - this.lon()) / 2);
228            double d = 2 * R * asin(
229                    sqrt(sinHalfLat*sinHalfLat +
230                            cos(toRadians(this.lat()))*cos(toRadians(other.lat()))*sinHalfLon*sinHalfLon));
231            // For points opposite to each other on the sphere,
232            // rounding errors could make the argument of asin greater than 1
233            // (This should almost never happen.)
234            if (java.lang.Double.isNaN(d)) {
235                System.err.println("Error: NaN in greatCircleDistance");
236                d = PI * R;
237            }
238            return d;
239        }
240    
241        /**
242         * Returns the heading, in radians, that you have to use to get from
243         * this lat/lon to another.
244         *
245         * (I don't know the original source of this formula, but see
246         * http://math.stackexchange.com/questions/720/how-to-calculate-a-heading-on-the-earths-surface
247         * for some hints how it is derived.)
248         *
249         * @param other the "destination" position
250         * @return heading in the range 0 <= hd < 2*PI
251         */
252        public double heading(LatLon other) {
253            double hd = atan2(sin(toRadians(this.lon() - other.lon())) * cos(toRadians(other.lat())),
254                    cos(toRadians(this.lat())) * sin(toRadians(other.lat())) -
255                    sin(toRadians(this.lat())) * cos(toRadians(other.lat())) * cos(toRadians(this.lon() - other.lon())));
256            hd %= 2 * PI;
257            if (hd < 0) {
258                hd += 2 * PI;
259            }
260            return hd;
261        }
262    
263        /**
264         * Returns this lat/lon pair in human-readable format.
265         *
266         * @return String in the format "lat=1.23456 deg, lon=2.34567 deg"
267         */
268        public String toDisplayString() {
269            NumberFormat nf = NumberFormat.getInstance();
270            nf.setMaximumFractionDigits(5);
271            return "lat=" + nf.format(lat()) + "\u00B0, lon=" + nf.format(lon()) + "\u00B0";
272        }
273    
274        public LatLon interpolate(LatLon ll2, double proportion) {
275            return new LatLon(this.lat() + proportion * (ll2.lat() - this.lat()),
276                    this.lon() + proportion * (ll2.lon() - this.lon()));
277        }
278    
279        public LatLon getCenter(LatLon ll2) {
280            return new LatLon((this.lat() + ll2.lat())/2.0, (this.lon() + ll2.lon())/2.0);
281        }
282    
283        @Override public String toString() {
284            return "LatLon[lat="+lat()+",lon="+lon()+"]";
285        }
286    
287        /**
288         * Returns the value rounded to OSM precisions, i.e. to
289         * LatLon.MAX_SERVER_PRECISION
290         *
291         * @return rounded value
292         */
293        public static double roundToOsmPrecision(double value) {
294            return Math.round(value * MAX_SERVER_INV_PRECISION) / MAX_SERVER_INV_PRECISION;
295        }
296    
297        /**
298         * Returns the value rounded to OSM precision. This function is now the same as
299         * {@link #roundToOsmPrecision(double)}, since the rounding error has been fixed.
300         *
301         * @return rounded value
302         */
303        public static double roundToOsmPrecisionStrict(double value) {
304            return roundToOsmPrecision(value);
305        }
306    
307        /**
308         * Replies a clone of this lat LatLon, rounded to OSM precisions, i.e. to
309         * MAX_SERVER_PRECISION
310         *
311         * @return a clone of this lat LatLon
312         */
313        public LatLon getRoundedToOsmPrecision() {
314            return new LatLon(
315                    roundToOsmPrecision(lat()),
316                    roundToOsmPrecision(lon())
317                    );
318        }
319    
320        /**
321         * Replies a clone of this lat LatLon, rounded to OSM precisions, i.e. to
322         * MAX_SERVER_PRECISION
323         *
324         * @return a clone of this lat LatLon
325         */
326        public LatLon getRoundedToOsmPrecisionStrict() {
327            return new LatLon(
328                    roundToOsmPrecisionStrict(lat()),
329                    roundToOsmPrecisionStrict(lon())
330                    );
331        }
332    
333        @Override
334        public int hashCode() {
335            final int prime = 31;
336            int result = super.hashCode();
337            long temp;
338            temp = java.lang.Double.doubleToLongBits(x);
339            result = prime * result + (int) (temp ^ (temp >>> 32));
340            temp = java.lang.Double.doubleToLongBits(y);
341            result = prime * result + (int) (temp ^ (temp >>> 32));
342            return result;
343        }
344    
345        @Override
346        public boolean equals(Object obj) {
347            if (this == obj)
348                return true;
349            if (!super.equals(obj))
350                return false;
351            if (getClass() != obj.getClass())
352                return false;
353            Coordinate other = (Coordinate) obj;
354            if (java.lang.Double.doubleToLongBits(x) != java.lang.Double.doubleToLongBits(other.x))
355                return false;
356            if (java.lang.Double.doubleToLongBits(y) != java.lang.Double.doubleToLongBits(other.y))
357                return false;
358            return true;
359        }
360    }