1 /* Copyright 2002-2026 CS GROUP
2 * Licensed to CS GROUP (CS) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * CS licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.orekit.bodies;
18
19 import java.text.NumberFormat;
20
21 import org.hipparchus.CalculusFieldElement;
22 import org.hipparchus.Field;
23 import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
24 import org.hipparchus.util.CompositeFormat;
25 import org.hipparchus.util.FastMath;
26 import org.hipparchus.util.FieldSinCos;
27 import org.hipparchus.util.MathUtils;
28
29 /** Point location relative to a 2D body surface, using {@link CalculusFieldElement}.
30 * <p>Instance of this class are guaranteed to be immutable.</p>
31 * @param <T> the type of the field elements
32 * @since 7.1
33 * @see BodyShape
34 * @see GeodeticPoint
35 * @author Luc Maisonobe
36 */
37 public class FieldGeodeticPoint<T extends CalculusFieldElement<T>> {
38
39 /** Latitude of the point (rad). */
40 private final T latitude;
41
42 /** Longitude of the point (rad). */
43 private final T longitude;
44
45 /** Altitude of the point (m). */
46 private final T altitude;
47
48 /** Zenith direction. */
49 private FieldVector3D<T> zenith;
50
51 /** Nadir direction. */
52 private FieldVector3D<T> nadir;
53
54 /** North direction. */
55 private FieldVector3D<T> north;
56
57 /** South direction. */
58 private FieldVector3D<T> south;
59
60 /** East direction. */
61 private FieldVector3D<T> east;
62
63 /** West direction. */
64 private FieldVector3D<T> west;
65
66 /** Build a new instance.
67 * <p>
68 * The angular coordinates will be normalized so that
69 * the latitude is between ±π/2 and the longitude is between ±π.
70 * </p>
71 * @param latitude latitude of the point (rad)
72 * @param longitude longitude of the point (rad)
73 * @param altitude altitude of the point (m)
74 */
75 public FieldGeodeticPoint(final T latitude, final T longitude,
76 final T altitude) {
77 final T zero = latitude.getField().getZero();
78 final T pi = zero.getPi();
79 T lat = MathUtils.normalizeAngle(latitude, pi.multiply(0.5));
80 T lon = MathUtils.normalizeAngle(longitude, zero);
81 if (lat.getReal() > pi.multiply(0.5).getReal()) {
82 // latitude is beyond the pole -> add 180 to longitude
83 lat = pi.subtract(lat);
84 lon = MathUtils.normalizeAngle(longitude.add(pi), zero);
85 }
86 this.latitude = lat;
87 this.longitude = lon;
88 this.altitude = altitude;
89 }
90
91 /** Build a new instance from a {@link GeodeticPoint}.
92 * @param field field to which the elements belong
93 * @param geodeticPoint geodetic point to convert
94 * @since 12.1
95 */
96 public FieldGeodeticPoint(final Field<T> field, final GeodeticPoint geodeticPoint) {
97 this(field.getZero().newInstance(geodeticPoint.getLatitude()),
98 field.getZero().newInstance(geodeticPoint.getLongitude()),
99 field.getZero().newInstance(geodeticPoint.getAltitude()));
100 }
101
102 /** Get the latitude.
103 * @return latitude, an angular value in the range [-π/2, π/2]
104 */
105 public T getLatitude() {
106 return latitude;
107 }
108
109 /** Get the longitude.
110 * @return longitude, an angular value in the range [-π, π]
111 */
112 public T getLongitude() {
113 return longitude;
114 }
115
116 /** Get the altitude.
117 * @return altitude
118 */
119 public T getAltitude() {
120 return altitude;
121 }
122
123 /** Get the direction above the point, expressed in parent shape frame.
124 * <p>The zenith direction is defined as the normal to local horizontal plane.</p>
125 * @return unit vector in the zenith direction
126 * @see #getNadir()
127 */
128 public FieldVector3D<T> getZenith() {
129 if (zenith == null) {
130 zenith = new FieldVector3D<>(longitude, latitude);
131 }
132 return zenith;
133 }
134
135 /** Get the direction below the point, expressed in parent shape frame.
136 * <p>The nadir direction is the opposite of zenith direction.</p>
137 * @return unit vector in the nadir direction
138 * @see #getZenith()
139 */
140 public FieldVector3D<T> getNadir() {
141 if (nadir == null) {
142 nadir = getZenith().negate();
143 }
144 return nadir;
145 }
146
147 /** Get the direction to the north of point, expressed in parent shape frame.
148 * <p>The north direction is defined in the horizontal plane
149 * (normal to zenith direction) and following the local meridian.</p>
150 * @return unit vector in the north direction
151 * @see #getSouth()
152 */
153 public FieldVector3D<T> getNorth() {
154 if (north == null) {
155 final FieldSinCos<T> scLat = FastMath.sinCos(latitude);
156 final FieldSinCos<T> scLon = FastMath.sinCos(longitude);
157 north = new FieldVector3D<>(scLon.cos().multiply(scLat.sin()).negate(),
158 scLon.sin().multiply(scLat.sin()).negate(),
159 scLat.cos());
160 }
161 return north;
162 }
163
164 /** Get the direction to the south of point, expressed in parent shape frame.
165 * <p>The south direction is the opposite of north direction.</p>
166 * @return unit vector in the south direction
167 * @see #getNorth()
168 */
169 public FieldVector3D<T> getSouth() {
170 if (south == null) {
171 south = getNorth().negate();
172 }
173 return south;
174 }
175
176 /** Get the direction to the east of point, expressed in parent shape frame.
177 * <p>The east direction is defined in the horizontal plane
178 * in order to complete direct triangle (east, north, zenith).</p>
179 * @return unit vector in the east direction
180 * @see #getWest()
181 */
182 public FieldVector3D<T> getEast() {
183 if (east == null) {
184 final FieldSinCos<T> scLon = FastMath.sinCos(longitude);
185 east = new FieldVector3D<>(scLon.sin().negate(),
186 scLon.cos(),
187 longitude.getField().getZero());
188 }
189 return east;
190 }
191
192 /** Get the direction to the west of point, expressed in parent shape frame.
193 * <p>The west direction is the opposite of east direction.</p>
194 * @return unit vector in the west direction
195 * @see #getEast()
196 */
197 public FieldVector3D<T> getWest() {
198 if (west == null) {
199 west = getEast().negate();
200 }
201 return west;
202 }
203
204 /**
205 * Get non-Field equivalent.
206 * @return geodetic point
207 * @since 12.2
208 */
209 public GeodeticPoint toGeodeticPoint() {
210 return new GeodeticPoint(latitude.getReal(), longitude.getReal(), altitude.getReal());
211 }
212
213 @Override
214 public boolean equals(final Object object) {
215 if (object instanceof FieldGeodeticPoint<?>) {
216 @SuppressWarnings("unchecked")
217 final FieldGeodeticPoint<T> other = (FieldGeodeticPoint<T>) object;
218 return getLatitude().equals(other.getLatitude()) &&
219 getLongitude().equals(other.getLongitude()) &&
220 getAltitude().equals(other.getAltitude());
221 }
222 return false;
223 }
224
225 @Override
226 public int hashCode() {
227 return getLatitude().hashCode() ^
228 getLongitude().hashCode() ^
229 getAltitude().hashCode();
230 }
231
232 @Override
233 public String toString() {
234 final NumberFormat format = CompositeFormat.getDefaultNumberFormat();
235 return "{lat: " +
236 format.format(FastMath.toDegrees(getLatitude().getReal())) +
237 " deg, lon: " +
238 format.format(FastMath.toDegrees(getLongitude().getReal())) +
239 " deg, alt: " +
240 format.format(getAltitude().getReal()) +
241 "}";
242 }
243
244 }