File: GeodesicExact.h

package info (click to toggle)
geographiclib 1.37-3
  • links: PTS, VCS
  • area: main
  • in suites: jessie, jessie-kfreebsd
  • size: 9,688 kB
  • ctags: 4,871
  • sloc: cpp: 31,440; sh: 11,632; cs: 9,411; ansic: 1,428; java: 1,333; python: 1,131; makefile: 758; xml: 381; pascal: 30
file content (603 lines) | stat: -rw-r--r-- 32,828 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
#pragma once
/**
 * \file NETGeographicLib/GeodesicExact.h
 * \brief Header for NETGeographicLib::GeodesicExact class
 *
 * NETGeographicLib is copyright (c) Scott Heiman (2013)
 * GeographicLib is Copyright (c) Charles Karney (2010-2012)
 * <charles@karney.com> and licensed under the MIT/X11 License.
 * For more information, see
 * http://geographiclib.sourceforge.net/
 **********************************************************************/
#include "NETGeographicLib.h"

namespace NETGeographicLib
{
    ref class GeodesicLineExact;
    /*!
    \brief .NET wrapper for GeographicLib::GeodesicExact.

    This class allows .NET applications to access GeographicLib::GeodesicExact.
    */
  /**
   * \brief .NET wrapper for GeographicLib::GeodesicExact.
   *
   * This class allows .NET applications to access GeographicLib::GeodesicExact.
   *
   * The equations for geodesics on an ellipsoid can be expressed in terms of
   * incomplete elliptic integrals.  The Geodesic class expands these integrals
   * in a series in the flattening \e f and this provides an accurate solution
   * for \e f &isin [-0.01, 0.01].  The GeodesicExact class computes the
   * ellitpic integrals directly and so provides a solution which is valid for
   * all \e f.  However, in practice, its use should be limited to about \e
   * b/\e a &isin; [0.01, 100] or \e f &isin; [-99, 0.99].
   *
   * For the WGS84 ellipsoid, these classes are 2--3 times \e slower than the
   * series solution and 2--3 times \e less \e accurate (because it's less easy
   * to control round-off errors with the elliptic integral formulation); i.e.,
   * the error is about 40 nm (40 nanometers) instead of 15 nm.  However the
   * error in the series solution scales as <i>f</i><sup>7</sup> while the
   * error in the elliptic integral solution depends weakly on \e f.  If the
   * quarter meridian distance is 10000 km and the ratio \e b/\e a = 1 &minus;
   * \e f is varied then the approximate maximum error (expressed as a
   * distance) is <pre>
   *       1 - f  error (nm)
   *       1/128     387
   *       1/64      345
   *       1/32      269
   *       1/16      210
   *       1/8       115
   *       1/4        69
   *       1/2        36
   *         1        15
   *         2        25
   *         4        96
   *         8       318
   *        16       985
   *        32      2352
   *        64      6008
   *       128     19024
   * </pre>
   *
   * The computation of the area in these classes is via a 30th order series.
   * This gives accurate results for \e b/\e a &isin; [1/2, 2]; the accuracy is
   * about 8 decimal digits for \e b/\e a &isin; [1/4, 4].
   *
   * See \ref geodellip for the formulation.  See the documentation on the
   * Geodesic class for additional information on the geodesics problems.
   *
   * C# Example:
   * \include example-GeodesicExact.cs
   * Managed C++ Example:
   * \include example-GeodesicExact.cpp
   * Visual Basic Example:
   * \include example-GeodesicExact.vb
   *
   * <B>INTERFACE DIFFERENCES:</B><BR>
   * A default constructor is provided that assumes WGS84 parameters.
   *
   * The MajorRadius, Flattening, and EllipsoidArea functions are
   * implemented as properties.
   *
   * The GenDirect, GenInverse, and Line functions accept the
   * "capabilities mask" as a NETGeographicLib::Mask rather than an
   * unsigned.
   **********************************************************************/
    public ref class GeodesicExact
    {
        private:
        // pointer to the unmanaged GeographicLib::GeodesicExact.
        const GeographicLib::GeodesicExact* m_pGeodesicExact;

        // the finalizer deletes the unmanaged memory.
        !GeodesicExact();
    public:
        /** \name Constructor
         **********************************************************************/
        ///@{
        /**
         * Constructor for a WGS84 ellipsoid
         **********************************************************************/
        GeodesicExact();

        /**
         * Constructor for a ellipsoid with
         *
         * @param[in] a equatorial radius (meters).
         * @param[in] f flattening of ellipsoid.  Setting \e f = 0 gives a sphere.
         *   Negative \e f gives a prolate ellipsoid.  If \e f > 1, set flattening
         *   to 1/\e f.
         * @exception GeographicErr if \e a or (1 &minus; \e f ) \e a is not
         *   positive.
         **********************************************************************/
        GeodesicExact(double a, double f);
        ///@}

        /**
         * The desstructor calls the finalizer.
         **********************************************************************/
        ~GeodesicExact()
        { this->!GeodesicExact(); }

        /** \name Direct geodesic problem specified in terms of distance.
         **********************************************************************/
        ///@{
        /**
         * Perform the direct geodesic calculation where the length of the geodesic
         * is specified in terms of distance.
         *
         * @param[in] lat1 latitude of point 1 (degrees).
         * @param[in] lon1 longitude of point 1 (degrees).
         * @param[in] azi1 azimuth at point 1 (degrees).
         * @param[in] s12 distance between point 1 and point 2 (meters); it can be
         *   signed.
         * @param[out] lat2 latitude of point 2 (degrees).
         * @param[out] lon2 longitude of point 2 (degrees).
         * @param[out] azi2 (forward) azimuth at point 2 (degrees).
         * @param[out] m12 reduced length of geodesic (meters).
         * @param[out] M12 geodesic scale of point 2 relative to point 1
         *   (dimensionless).
         * @param[out] M21 geodesic scale of point 1 relative to point 2
         *   (dimensionless).
         * @param[out] S12 area under the geodesic (meters<sup>2</sup>).
         * @return \e a12 arc length of between point 1 and point 2 (degrees).
         *
         * \e lat1 should be in the range [&minus;90&deg;, 90&deg;]; \e lon1 and \e
         * azi1 should be in the range [&minus;540&deg;, 540&deg;).  The values of
         * \e lon2 and \e azi2 returned are in the range [&minus;180&deg;,
         * 180&deg;).
         *
         * If either point is at a pole, the azimuth is defined by keeping the
         * longitude fixed, writing \e lat = &plusmn;(90&deg; &minus; &epsilon;),
         * and taking the limit &epsilon; &rarr; 0+.  An arc length greater that
         * 180&deg; signifies a geodesic which is not a shortest path.  (For a
         * prolate ellipsoid, an additional condition is necessary for a shortest
         * path: the longitudinal extent must not exceed of 180&deg;.)
         *
         * The following functions are overloaded versions of GeodesicExact::Direct
         * which omit some of the output parameters.  Note, however, that the arc
         * length is always computed and returned as the function value.
         **********************************************************************/
        double Direct(double lat1, double lon1, double azi1, double s12,
                          [System::Runtime::InteropServices::Out] double% lat2,
                          [System::Runtime::InteropServices::Out] double% lon2,
                          [System::Runtime::InteropServices::Out] double% azi2,
                          [System::Runtime::InteropServices::Out] double% m12,
                          [System::Runtime::InteropServices::Out] double% M12,
                          [System::Runtime::InteropServices::Out] double% M21,
                          [System::Runtime::InteropServices::Out] double% S12);

        /**
         * See the documentation for GeodesicExact::Direct.
         **********************************************************************/
        double Direct(double lat1, double lon1, double azi1, double s12,
                          [System::Runtime::InteropServices::Out] double% lat2,
                          [System::Runtime::InteropServices::Out] double% lon2);

        /**
         * See the documentation for GeodesicExact::Direct.
         **********************************************************************/
        double Direct(double lat1, double lon1, double azi1, double s12,
                          [System::Runtime::InteropServices::Out] double% lat2,
                          [System::Runtime::InteropServices::Out] double% lon2,
                          [System::Runtime::InteropServices::Out] double% azi2);

        /**
         * See the documentation for GeodesicExact::Direct.
         **********************************************************************/
        double Direct(double lat1, double lon1, double azi1, double s12,
                          [System::Runtime::InteropServices::Out] double% lat2,
                          [System::Runtime::InteropServices::Out] double% lon2,
                          [System::Runtime::InteropServices::Out] double% azi2,
                          [System::Runtime::InteropServices::Out] double% m12);

        /**
         * See the documentation for GeodesicExact::Direct.
         **********************************************************************/
        double Direct(double lat1, double lon1, double azi1, double s12,
                          [System::Runtime::InteropServices::Out] double% lat2,
                          [System::Runtime::InteropServices::Out] double% lon2,
                          [System::Runtime::InteropServices::Out] double% azi2,
                          [System::Runtime::InteropServices::Out] double% M12,
                          [System::Runtime::InteropServices::Out] double% M21);

        /**
         * See the documentation for GeodesicExact::Direct.
         **********************************************************************/
        double Direct(double lat1, double lon1, double azi1, double s12,
                          [System::Runtime::InteropServices::Out] double% lat2,
                          [System::Runtime::InteropServices::Out] double% lon2,
                          [System::Runtime::InteropServices::Out] double% azi2,
                          [System::Runtime::InteropServices::Out] double% m12,
                          [System::Runtime::InteropServices::Out] double% M12,
                          [System::Runtime::InteropServices::Out] double% M21);
        ///@}

        /** \name Direct geodesic problem specified in terms of arc length.
         **********************************************************************/
        ///@{
        /**
         * Perform the direct geodesic calculation where the length of the geodesic
         * is specified in terms of arc length.
         *
         * @param[in] lat1 latitude of point 1 (degrees).
         * @param[in] lon1 longitude of point 1 (degrees).
         * @param[in] azi1 azimuth at point 1 (degrees).
         * @param[in] a12 arc length between point 1 and point 2 (degrees); it can
         *   be signed.
         * @param[out] lat2 latitude of point 2 (degrees).
         * @param[out] lon2 longitude of point 2 (degrees).
         * @param[out] azi2 (forward) azimuth at point 2 (degrees).
         * @param[out] s12 distance between point 1 and point 2 (meters).
         * @param[out] m12 reduced length of geodesic (meters).
         * @param[out] M12 geodesic scale of point 2 relative to point 1
         *   (dimensionless).
         * @param[out] M21 geodesic scale of point 1 relative to point 2
         *   (dimensionless).
         * @param[out] S12 area under the geodesic (meters<sup>2</sup>).
         *
         * \e lat1 should be in the range [&minus;90&deg;, 90&deg;]; \e lon1 and \e
         * azi1 should be in the range [&minus;540&deg;, 540&deg;).  The values of
         * \e lon2 and \e azi2 returned are in the range [&minus;180&deg;,
         * 180&deg;).
         *
         * If either point is at a pole, the azimuth is defined by keeping the
         * longitude fixed, writing \e lat = &plusmn;(90&deg; &minus; &epsilon;),
         * and taking the limit &epsilon; &rarr; 0+.  An arc length greater that
         * 180&deg; signifies a geodesic which is not a shortest path.  (For a
         * prolate ellipsoid, an additional condition is necessary for a shortest
         * path: the longitudinal extent must not exceed of 180&deg;.)
         *
         * The following functions are overloaded versions of GeodesicExact::Direct
         * which omit some of the output parameters.
         **********************************************************************/
        void ArcDirect(double lat1, double lon1, double azi1, double a12,
                       [System::Runtime::InteropServices::Out] double% lat2,
                       [System::Runtime::InteropServices::Out] double% lon2,
                       [System::Runtime::InteropServices::Out] double% azi2,
                       [System::Runtime::InteropServices::Out] double% s12,
                       [System::Runtime::InteropServices::Out] double% m12,
                       [System::Runtime::InteropServices::Out] double% M12,
                       [System::Runtime::InteropServices::Out] double% M21,
                       [System::Runtime::InteropServices::Out] double% S12);

        /**
         * See the documentation for GeodesicExact::ArcDirect.
         **********************************************************************/
        void ArcDirect(double lat1, double lon1, double azi1, double a12,
                       [System::Runtime::InteropServices::Out] double% lat2,
                       [System::Runtime::InteropServices::Out] double% lon2);

        /**
         * See the documentation for GeodesicExact::ArcDirect.
         **********************************************************************/
        void ArcDirect(double lat1, double lon1, double azi1, double a12,
                       [System::Runtime::InteropServices::Out] double% lat2,
                       [System::Runtime::InteropServices::Out] double% lon2,
                       [System::Runtime::InteropServices::Out] double% azi2);

        /**
         * See the documentation for GeodesicExact::ArcDirect.
         **********************************************************************/
        void ArcDirect(double lat1, double lon1, double azi1, double a12,
                       [System::Runtime::InteropServices::Out] double% lat2,
                       [System::Runtime::InteropServices::Out] double% lon2,
                       [System::Runtime::InteropServices::Out] double% azi2,
                       [System::Runtime::InteropServices::Out] double% s12);

        /**
         * See the documentation for GeodesicExact::ArcDirect.
         **********************************************************************/
        void ArcDirect(double lat1, double lon1, double azi1, double a12,
                       [System::Runtime::InteropServices::Out] double% lat2,
                       [System::Runtime::InteropServices::Out] double% lon2,
                       [System::Runtime::InteropServices::Out] double% azi2,
                       [System::Runtime::InteropServices::Out] double% s12,
                       [System::Runtime::InteropServices::Out] double% m12);

        /**
         * See the documentation for GeodesicExact::ArcDirect.
         **********************************************************************/
        void ArcDirect(double lat1, double lon1, double azi1, double a12,
                       [System::Runtime::InteropServices::Out] double% lat2,
                       [System::Runtime::InteropServices::Out] double% lon2,
                       [System::Runtime::InteropServices::Out] double% azi2,
                       [System::Runtime::InteropServices::Out] double% s12,
                       [System::Runtime::InteropServices::Out] double% M12,
                       [System::Runtime::InteropServices::Out] double% M21);

        /**
         * See the documentation for GeodesicExact::ArcDirect.
         **********************************************************************/
        void ArcDirect(double lat1, double lon1, double azi1, double a12,
                       [System::Runtime::InteropServices::Out] double% lat2,
                       [System::Runtime::InteropServices::Out] double% lon2,
                       [System::Runtime::InteropServices::Out] double% azi2,
                       [System::Runtime::InteropServices::Out] double% s12,
                       [System::Runtime::InteropServices::Out] double% m12,
                       [System::Runtime::InteropServices::Out] double% M12,
                       [System::Runtime::InteropServices::Out] double% M21);
        ///@}

        /** \name General version of the direct geodesic solution.
         **********************************************************************/
        ///@{

        /**
         * The general direct geodesic calculation.  GeodesicExact::Direct and
         * GeodesicExact::ArcDirect are defined in terms of this function.
         *
         * @param[in] lat1 latitude of point 1 (degrees).
         * @param[in] lon1 longitude of point 1 (degrees).
         * @param[in] azi1 azimuth at point 1 (degrees).
         * @param[in] arcmode boolean flag determining the meaning of the second
         *   parameter.
         * @param[in] s12_a12 if \e arcmode is false, this is the distance between
         *   point 1 and point 2 (meters); otherwise it is the arc length between
         *   point 1 and point 2 (degrees); it can be signed.
         * @param[in] outmask a bitor'ed combination of  NETGeographicLib::Mask values
         *   specifying which of the following parameters should be set.
         * @param[out] lat2 latitude of point 2 (degrees).
         * @param[out] lon2 longitude of point 2 (degrees).
         * @param[out] azi2 (forward) azimuth at point 2 (degrees).
         * @param[out] s12 distance between point 1 and point 2 (meters).
         * @param[out] m12 reduced length of geodesic (meters).
         * @param[out] M12 geodesic scale of point 2 relative to point 1
         *   (dimensionless).
         * @param[out] M21 geodesic scale of point 1 relative to point 2
         *   (dimensionless).
         * @param[out] S12 area under the geodesic (meters<sup>2</sup>).
         * @return \e a12 arc length of between point 1 and point 2 (degrees).
         *
         * The  NETGeographicLib::Mask values possible for \e outmask are
         * - \e outmask |= NETGeographicLib::Mask::LATITUDE for the latitude \e lat2;
         * - \e outmask |= NETGeographicLib::Mask::LONGITUDE for the latitude \e lon2;
         * - \e outmask |= NETGeographicLib::Mask::AZIMUTH for the latitude \e azi2;
         * - \e outmask |= NETGeographicLib::Mask::DISTANCE for the distance \e s12;
         * - \e outmask |= NETGeographicLib::Mask::REDUCEDLENGTH for the reduced length \e
         *   m12;
         * - \e outmask |= NETGeographicLib::Mask::GEODESICSCALE for the geodesic scales \e
         *   M12 and \e M21;
         * - \e outmask |= NETGeographicLib::Mask::AREA for the area \e S12;
         * - \e outmask |= NETGeographicLib::Mask::ALL for all of the above.
         * .
         * The function value \e a12 is always computed and returned and this
         * equals \e s12_a12 is \e arcmode is true.  If \e outmask includes
         * GeodesicExact::DISTANCE and \e arcmode is false, then \e s12 = \e
         * s12_a12.  It is not necessary to include  NETGeographicLib::Mask::DISTANCE_IN in
         * \e outmask; this is automatically included is \e arcmode is false.
         **********************************************************************/
        double GenDirect(double lat1, double lon1, double azi1,
                        bool arcmode, double s12_a12, NETGeographicLib::Mask outmask,
                        [System::Runtime::InteropServices::Out] double% lat2,
                        [System::Runtime::InteropServices::Out] double% lon2,
                        [System::Runtime::InteropServices::Out] double% azi2,
                        [System::Runtime::InteropServices::Out] double% s12,
                        [System::Runtime::InteropServices::Out] double% m12,
                        [System::Runtime::InteropServices::Out] double% M12,
                        [System::Runtime::InteropServices::Out] double% M21,
                        [System::Runtime::InteropServices::Out] double% S12);
        ///@}

        /** \name Inverse geodesic problem.
         **********************************************************************/
        ///@{
        /**
         * Perform the inverse geodesic calculation.
         *
         * @param[in] lat1 latitude of point 1 (degrees).
         * @param[in] lon1 longitude of point 1 (degrees).
         * @param[in] lat2 latitude of point 2 (degrees).
         * @param[in] lon2 longitude of point 2 (degrees).
         * @param[out] s12 distance between point 1 and point 2 (meters).
         * @param[out] azi1 azimuth at point 1 (degrees).
         * @param[out] azi2 (forward) azimuth at point 2 (degrees).
         * @param[out] m12 reduced length of geodesic (meters).
         * @param[out] M12 geodesic scale of point 2 relative to point 1
         *   (dimensionless).
         * @param[out] M21 geodesic scale of point 1 relative to point 2
         *   (dimensionless).
         * @param[out] S12 area under the geodesic (meters<sup>2</sup>).
         * @return \e a12 arc length of between point 1 and point 2 (degrees).
         *
         * \e lat1 and \e lat2 should be in the range [&minus;90&deg;, 90&deg;]; \e
         * lon1 and \e lon2 should be in the range [&minus;540&deg;, 540&deg;).
         * The values of \e azi1 and \e azi2 returned are in the range
         * [&minus;180&deg;, 180&deg;).
         *
         * If either point is at a pole, the azimuth is defined by keeping the
         * longitude fixed, writing \e lat = &plusmn;(90&deg; &minus; &epsilon;),
         * and taking the limit &epsilon; &rarr; 0+.
         *
         * The following functions are overloaded versions of GeodesicExact::Inverse
         * which omit some of the output parameters.  Note, however, that the arc
         * length is always computed and returned as the function value.
         **********************************************************************/
        double Inverse(double lat1, double lon1, double lat2, double lon2,
                           [System::Runtime::InteropServices::Out] double% s12,
                           [System::Runtime::InteropServices::Out] double% azi1,
                           [System::Runtime::InteropServices::Out] double% azi2,
                           [System::Runtime::InteropServices::Out] double% m12,
                           [System::Runtime::InteropServices::Out] double% M12,
                           [System::Runtime::InteropServices::Out] double% M21,
                           [System::Runtime::InteropServices::Out] double% S12);

        /**
         * See the documentation for GeodesicExact::Inverse.
         **********************************************************************/
        double Inverse(double lat1, double lon1, double lat2, double lon2,
                           [System::Runtime::InteropServices::Out] double% s12);

        /**
         * See the documentation for GeodesicExact::Inverse.
         **********************************************************************/
        double Inverse(double lat1, double lon1, double lat2, double lon2,
                           [System::Runtime::InteropServices::Out] double% azi1,
                           [System::Runtime::InteropServices::Out] double% azi2);

        /**
         * See the documentation for GeodesicExact::Inverse.
         **********************************************************************/
        double Inverse(double lat1, double lon1, double lat2, double lon2,
                    [System::Runtime::InteropServices::Out] double% s12,
                    [System::Runtime::InteropServices::Out] double% azi1,
                    [System::Runtime::InteropServices::Out] double% azi2);

        /**
         * See the documentation for GeodesicExact::Inverse.
         **********************************************************************/
        double Inverse(double lat1, double lon1, double lat2, double lon2,
                    [System::Runtime::InteropServices::Out] double% s12,
                    [System::Runtime::InteropServices::Out] double% azi1,
                    [System::Runtime::InteropServices::Out] double% azi2,
                    [System::Runtime::InteropServices::Out] double% m12);

        /**
         * See the documentation for GeodesicExact::Inverse.
         **********************************************************************/
        double Inverse(double lat1, double lon1, double lat2, double lon2,
                    [System::Runtime::InteropServices::Out] double% s12,
                    [System::Runtime::InteropServices::Out] double% azi1,
                    [System::Runtime::InteropServices::Out] double% azi2,
                    [System::Runtime::InteropServices::Out] double% M12,
                    [System::Runtime::InteropServices::Out] double% M21);

        /**
         * See the documentation for GeodesicExact::Inverse.
         **********************************************************************/
        double Inverse(double lat1, double lon1, double lat2, double lon2,
                    [System::Runtime::InteropServices::Out] double% s12,
                    [System::Runtime::InteropServices::Out] double% azi1,
                    [System::Runtime::InteropServices::Out] double% azi2,
                    [System::Runtime::InteropServices::Out] double% m12,
                    [System::Runtime::InteropServices::Out] double% M12,
                    [System::Runtime::InteropServices::Out] double% M21);
        ///@}

        /** \name General version of inverse geodesic solution.
         **********************************************************************/
        ///@{
        /**
         * The general inverse geodesic calculation.  GeodesicExact::Inverse is
         * defined in terms of this function.
         *
         * @param[in] lat1 latitude of point 1 (degrees).
         * @param[in] lon1 longitude of point 1 (degrees).
         * @param[in] lat2 latitude of point 2 (degrees).
         * @param[in] lon2 longitude of point 2 (degrees).
         * @param[in] outmask a bitor'ed combination of  NETGeographicLib::Mask values
         *   specifying which of the following parameters should be set.
         * @param[out] s12 distance between point 1 and point 2 (meters).
         * @param[out] azi1 azimuth at point 1 (degrees).
         * @param[out] azi2 (forward) azimuth at point 2 (degrees).
         * @param[out] m12 reduced length of geodesic (meters).
         * @param[out] M12 geodesic scale of point 2 relative to point 1
         *   (dimensionless).
         * @param[out] M21 geodesic scale of point 1 relative to point 2
         *   (dimensionless).
         * @param[out] S12 area under the geodesic (meters<sup>2</sup>).
         * @return \e a12 arc length of between point 1 and point 2 (degrees).
         *
         * The NETGeographicLib::Mask values possible for \e outmask are
         * - \e outmask |= NETGeographicLib::Mask::DISTANCE for the distance \e s12;
         * - \e outmask |= NETGeographicLib::Mask::AZIMUTH for the latitude \e azi2;
         * - \e outmask |= NETGeographicLib::Mask::REDUCEDLENGTH for the reduced length \e
         *   m12;
         * - \e outmask |= NETGeographicLib::Mask::GEODESICSCALE for the geodesic scales \e
         *   M12 and \e M21;
         * - \e outmask |= NETGeographicLib::Mask::AREA for the area \e S12;
         * - \e outmask |= NETGeographicLib::Mask::ALL for all of the above.
         * .
         * The arc length is always computed and returned as the function value.
         **********************************************************************/
        double GenInverse(double lat1, double lon1, double lat2, double lon2,
                        NETGeographicLib::Mask outmask,
                        [System::Runtime::InteropServices::Out] double% s12,
                        [System::Runtime::InteropServices::Out] double% azi1,
                        [System::Runtime::InteropServices::Out] double% azi2,
                        [System::Runtime::InteropServices::Out] double% m12,
                        [System::Runtime::InteropServices::Out] double% M12,
                        [System::Runtime::InteropServices::Out] double% M21,
                        [System::Runtime::InteropServices::Out] double% S12);
        ///@}

        /** \name Interface to GeodesicLineExact.
         **********************************************************************/
        ///@{

        /**
         * Set up to compute several points on a single geodesic.
         *
         * @param[in] lat1 latitude of point 1 (degrees).
         * @param[in] lon1 longitude of point 1 (degrees).
         * @param[in] azi1 azimuth at point 1 (degrees).
         * @param[in] caps bitor'ed combination of NETGeographicLib::Mask values
         *   specifying the capabilities the GeodesicLineExact object should
         *   possess, i.e., which quantities can be returned in calls to
         *   GeodesicLineExact::Position.
         * @return a GeodesicLineExact object.
         *
         * \e lat1 should be in the range [&minus;90&deg;, 90&deg;]; \e lon1 and \e
         * azi1 should be in the range [&minus;540&deg;, 540&deg;).
         *
         * The GeodesicExact::mask values are
         * - \e caps |= NETGeographicLib::Mask::LATITUDE for the latitude \e lat2; this is
         *   added automatically;
         * - \e caps |= NETGeographicLib::Mask::LONGITUDE for the latitude \e lon2;
         * - \e caps |= NETGeographicLib::Mask::AZIMUTH for the azimuth \e azi2; this is
         *   added automatically;
         * - \e caps |= NETGeographicLib::Mask::DISTANCE for the distance \e s12;
         * - \e caps |= NETGeographicLib::Mask::REDUCEDLENGTH for the reduced length \e m12;
         * - \e caps |= NETGeographicLib::Mask::GEODESICSCALE for the geodesic scales \e M12
         *   and \e M21;
         * - \e caps |= NETGeographicLib::Mask::AREA for the area \e S12;
         * - \e caps |= NETGeographicLib::Mask::DISTANCE_IN permits the length of the
         *   geodesic to be given in terms of \e s12; without this capability the
         *   length can only be specified in terms of arc length;
         * - \e caps |= GeodesicExact::ALL for all of the above.
         * .
         * The default value of \e caps is GeodesicExact::ALL which turns on all
         * the capabilities.
         *
         * If the point is at a pole, the azimuth is defined by keeping \e lon1
         * fixed, writing \e lat1 = &plusmn;(90 &minus; &epsilon;), and taking the
         * limit &epsilon; &rarr; 0+.
         **********************************************************************/
        GeodesicLineExact^ Line(double lat1, double lon1, double azi1,
            NETGeographicLib::Mask caps );

        ///@}

        /** \name Inspector functions.
         **********************************************************************/
        ///@{

        /**
         * @return \e a the equatorial radius of the ellipsoid (meters).  This is
         *   the value used in the constructor.
         **********************************************************************/
        property double MajorRadius { double get(); }

        /**
         * @return \e f the  flattening of the ellipsoid.  This is the
         *   value used in the constructor.
         **********************************************************************/
        property double Flattening { double get(); }

        /**
         * @return total area of ellipsoid in meters<sup>2</sup>.  The area of a
         *   polygon encircling a pole can be found by adding
         *   GeodesicExact::EllipsoidArea()/2 to the sum of \e S12 for each side of
         *   the polygon.
         **********************************************************************/
        property double EllipsoidArea { double get(); }
        ///@}

        /**
         * @return A pointer to the unmanaged GeographicLib::GeodesicExact.
         *
         * This function is for internal use only.
         **********************************************************************/
        System::IntPtr^ GetUnmanaged();
    };
} // namespace NETGeographicLib