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
|
#pragma once
/**
* \file NETGeographicLib/MagneticModel.h
* \brief Header for NETGeographicLib::MagneticModel 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/
**********************************************************************/
namespace NETGeographicLib
{
ref class MagneticCircle;
ref class Geocentric;
/**
* \brief .NET wrapper for GeographicLib::MagneticModel.
*
* This class allows .NET applications to access GeographicLib::MagneticModel.
*
* Evaluate the earth's magnetic field according to a model. At present only
* internal magnetic fields are handled. These are due to the earth's code
* and crust; these vary slowly (over many years). Excluded are the effects
* of currents in the ionosphere and magnetosphere which have daily and
* annual variations.
*
* See \ref magnetic for details of how to install the magnetic model and the
* data format.
*
* See
* - General information:
* - http://geomag.org/models/index.html
* - WMM2010:
* - http://ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml
* - http://ngdc.noaa.gov/geomag/WMM/data/WMM2010/WMM2010COF.zip
* - IGRF11:
* - http://ngdc.noaa.gov/IAGA/vmod/igrf.html
* - http://ngdc.noaa.gov/IAGA/vmod/igrf11coeffs.txt
* - http://ngdc.noaa.gov/IAGA/vmod/geomag70_linux.tar.gz
* - EMM2010:
* - http://ngdc.noaa.gov/geomag/EMM/index.html
* - http://ngdc.noaa.gov/geomag/EMM/data/geomag/EMM2010_Sph_Windows_Linux.zip
*
* C# Example:
* \include example-MagneticModel.cs
* Managed C++ Example:
* \include example-MagneticModel.cpp
* Visual Basic Example:
* \include example-MagneticModel.vb
*
* <B>INTERFACE DIFFERENCES:</B><BR>
* The () operator has been replaced with Field.
*
* The following functions are implemented as properties:
* Description, DateTime, MagneticFile, MagneticModelName,
* MagneticModelDirectory, MinHeight, MaxHeight, MinTime, MaxTime,
* MajorRadius, and Flattening.
**********************************************************************/
public ref class MagneticModel
{
private:
// The pointer to the unmanaged GeographicLib::MagneticModel.
const GeographicLib::MagneticModel* m_pMagneticModel;
// The finalizer frees the unmanaged memory when the object is destroyed.
!MagneticModel(void);
public:
/** \name Setting up the magnetic model
**********************************************************************/
///@{
/**
* Construct a magnetic model.
*
* @param[in] name the name of the model.
* @param[in] path (optional) directory for data file.
* @param[in] earth (optional) Geocentric object for converting
* coordinates.
* @exception GeographicErr if the data file cannot be found, is
* unreadable, or is corrupt.
* @exception std::bad_alloc if the memory necessary for storing the model
* can't be allocated.
*
* A filename is formed by appending ".wmm" (World Magnetic Model) to the
* name. If \e path is specified (and is non-empty), then the file is
* loaded from directory, \e path. Otherwise the path is given by the
* DefaultMagneticPath().
*
* This file contains the metadata which specifies the properties of the
* model. The coefficients for the spherical harmonic sums are obtained
* from a file obtained by appending ".cof" to metadata file (so the
* filename ends in ".wwm.cof").
*
* The model is not tied to a particular ellipsoidal model of the earth.
* The final earth argument to the constructor specifies an ellipsoid to
* allow geodetic coordinates to the transformed into the spherical
* coordinates used in the spherical harmonic sum.
**********************************************************************/
MagneticModel(System::String^ name,
System::String^ path,
Geocentric^ earth);
/**
* Construct a magnetic model that assumes the WGS84 ellipsoid.
*
* @param[in] name the name of the model.
* @param[in] path (optional) directory for data file.
* @exception GeographicErr if the data file cannot be found, is
* unreadable, or is corrupt.
* @exception GeographicErr if the memory necessary for storing the model
* can't be allocated.
*
* A filename is formed by appending ".wmm" (World Magnetic Model) to the
* name. If \e path is specified (and is non-empty), then the file is
* loaded from directory, \e path. Otherwise the path is given by the
* DefaultMagneticPath().
*
* This file contains the metadata which specifies the properties of the
* model. The coefficients for the spherical harmonic sums are obtained
* from a file obtained by appending ".cof" to metadata file (so the
* filename ends in ".wwm.cof").
*
* The model is not tied to a particular ellipsoidal model of the earth.
* The final earth argument to the constructor specifies an ellipsoid to
* allow geodetic coordinates to the transformed into the spherical
* coordinates used in the spherical harmonic sum.
**********************************************************************/
MagneticModel(System::String^ name,
System::String^ path);
///@}
/**
* The destructor calls the finalizer.
**********************************************************************/
~MagneticModel()
{ this->!MagneticModel(); }
/** \name Compute the magnetic field
**********************************************************************/
///@{
/**
* Evaluate the components of the geomagnetic field.
*
* @param[in] t the time (years).
* @param[in] lat latitude of the point (degrees).
* @param[in] lon longitude of the point (degrees).
* @param[in] h the height of the point above the ellipsoid (meters).
* @param[out] Bx the easterly component of the magnetic field (nanotesla).
* @param[out] By the northerly component of the magnetic field (nanotesla).
* @param[out] Bz the vertical (up) component of the magnetic field
* (nanotesla).
**********************************************************************/
void Field(double t, double lat, double lon, double h,
[System::Runtime::InteropServices::Out] double% Bx,
[System::Runtime::InteropServices::Out] double% By,
[System::Runtime::InteropServices::Out] double% Bz);
/**
* Evaluate the components of the geomagnetic field and their time
* derivatives
*
* @param[in] t the time (years).
* @param[in] lat latitude of the point (degrees).
* @param[in] lon longitude of the point (degrees).
* @param[in] h the height of the point above the ellipsoid (meters).
* @param[out] Bx the easterly component of the magnetic field (nanotesla).
* @param[out] By the northerly component of the magnetic field (nanotesla).
* @param[out] Bz the vertical (up) component of the magnetic field
* (nanotesla).
* @param[out] Bxt the rate of change of \e Bx (nT/yr).
* @param[out] Byt the rate of change of \e By (nT/yr).
* @param[out] Bzt the rate of change of \e Bz (nT/yr).
**********************************************************************/
void Field(double t, double lat, double lon, double h,
[System::Runtime::InteropServices::Out] double% Bx,
[System::Runtime::InteropServices::Out] double% By,
[System::Runtime::InteropServices::Out] double% Bz,
[System::Runtime::InteropServices::Out] double% Bxt,
[System::Runtime::InteropServices::Out] double% Byt,
[System::Runtime::InteropServices::Out] double% Bzt);
/**
* Create a MagneticCircle object to allow the geomagnetic field at many
* points with constant \e lat, \e h, and \e t and varying \e lon to be
* computed efficiently.
*
* @param[in] t the time (years).
* @param[in] lat latitude of the point (degrees).
* @param[in] h the height of the point above the ellipsoid (meters).
* @exception std::bad_alloc if the memory necessary for creating a
* MagneticCircle can't be allocated.
* @return a MagneticCircle object whose MagneticCircle::Field(double
* lon) member function computes the field at particular values of \e
* lon.
*
* If the field at several points on a circle of latitude need to be
* calculated then creating a MagneticCircle and using its member functions
* will be substantially faster, especially for high-degree models.
**********************************************************************/
MagneticCircle^ Circle(double t, double lat, double h);
/**
* Compute various quantities dependent on the magnetic field.
*
* @param[in] Bx the \e x (easterly) component of the magnetic field (nT).
* @param[in] By the \e y (northerly) component of the magnetic field (nT).
* @param[in] Bz the \e z (vertical, up positive) component of the magnetic
* field (nT).
* @param[out] H the horizontal magnetic field (nT).
* @param[out] F the total magnetic field (nT).
* @param[out] D the declination of the field (degrees east of north).
* @param[out] I the inclination of the field (degrees down from
* horizontal).
**********************************************************************/
static void FieldComponents(double Bx, double By, double Bz,
[System::Runtime::InteropServices::Out] double% H,
[System::Runtime::InteropServices::Out] double% F,
[System::Runtime::InteropServices::Out] double% D,
[System::Runtime::InteropServices::Out] double% I);
/**
* Compute various quantities dependent on the magnetic field and its rate
* of change.
*
* @param[in] Bx the \e x (easterly) component of the magnetic field (nT).
* @param[in] By the \e y (northerly) component of the magnetic field (nT).
* @param[in] Bz the \e z (vertical, up positive) component of the magnetic
* field (nT).
* @param[in] Bxt the rate of change of \e Bx (nT/yr).
* @param[in] Byt the rate of change of \e By (nT/yr).
* @param[in] Bzt the rate of change of \e Bz (nT/yr).
* @param[out] H the horizontal magnetic field (nT).
* @param[out] F the total magnetic field (nT).
* @param[out] D the declination of the field (degrees east of north).
* @param[out] I the inclination of the field (degrees down from
* horizontal).
* @param[out] Ht the rate of change of \e H (nT/yr).
* @param[out] Ft the rate of change of \e F (nT/yr).
* @param[out] Dt the rate of change of \e D (degrees/yr).
* @param[out] It the rate of change of \e I (degrees/yr).
**********************************************************************/
static void FieldComponents(double Bx, double By, double Bz,
double Bxt, double Byt, double Bzt,
[System::Runtime::InteropServices::Out] double% H,
[System::Runtime::InteropServices::Out] double% F,
[System::Runtime::InteropServices::Out] double% D,
[System::Runtime::InteropServices::Out] double% I,
[System::Runtime::InteropServices::Out] double% Ht,
[System::Runtime::InteropServices::Out] double% Ft,
[System::Runtime::InteropServices::Out] double% Dt,
[System::Runtime::InteropServices::Out] double% It);
///@}
/** \name Inspector functions
**********************************************************************/
///@{
/**
* @return the description of the magnetic model, if available, from the
* Description file in the data file; if absent, return "NONE".
**********************************************************************/
property System::String^ Description { System::String^ get(); }
/**
* @return date of the model, if available, from the ReleaseDate field in
* the data file; if absent, return "UNKNOWN".
**********************************************************************/
property System::String^ DateTime { System::String^ get(); }
/**
* @return full file name used to load the magnetic model.
**********************************************************************/
property System::String^ MagneticFile { System::String^ get(); }
/**
* @return "name" used to load the magnetic model (from the first argument
* of the constructor, but this may be overridden by the model file).
**********************************************************************/
property System::String^ MagneticModelName { System::String^ get(); }
/**
* @return directory used to load the magnetic model.
**********************************************************************/
property System::String^ MagneticModelDirectory { System::String^ get(); }
/**
* @return the minimum height above the ellipsoid (in meters) for which
* this MagneticModel should be used.
*
* Because the model will typically provide useful results
* slightly outside the range of allowed heights, no check of \e t
* argument is made by MagneticModel::Field() or
* MagneticModel::Circle.
**********************************************************************/
property double MinHeight { double get(); }
/**
* @return the maximum height above the ellipsoid (in meters) for which
* this MagneticModel should be used.
*
* Because the model will typically provide useful results
* slightly outside the range of allowed heights, no check of \e t
* argument is made by MagneticModel::Field() or
* MagneticModel::Circle.
**********************************************************************/
property double MaxHeight { double get(); }
/**
* @return the minimum time (in years) for which this MagneticModel should
* be used.
*
* Because the model will typically provide useful results
* slightly outside the range of allowed times, no check of \e t
* argument is made by MagneticModel::Field() or
* MagneticModel::Circle.
**********************************************************************/
property double MinTime { double get(); }
/**
* @return the maximum time (in years) for which this MagneticModel should
* be used.
*
* Because the model will typically provide useful results
* slightly outside the range of allowed times, no check of \e t
* argument is made by MagneticModel::Field() or
* MagneticModel::Circle.
**********************************************************************/
property double MaxTime { double get(); }
/**
* @return \e a the equatorial radius of the ellipsoid (meters). This is
* the value of \e a inherited from the Geocentric object used in the
* constructor.
**********************************************************************/
property double MajorRadius { double get(); }
/**
* @return \e f the flattening of the ellipsoid. This is the value
* inherited from the Geocentric object used in the constructor.
**********************************************************************/
property double Flattening { double get(); }
///@}
/**
* @return the default path for magnetic model data files.
*
* This is the value of the environment variable
* GEOGRAPHICLIB_MAGNETIC_PATH, if set; otherwise, it is
* $GEOGRAPHICLIB_DATA/magnetic if the environment variable
* GEOGRAPHICLIB_DATA is set; otherwise, it is a compile-time default
* (/usr/local/share/GeographicLib/magnetic on non-Windows systems and
* C:/ProgramData/GeographicLib/magnetic on Windows systems).
**********************************************************************/
static System::String^ DefaultMagneticPath();
/**
* @return the default name for the magnetic model.
*
* This is the value of the environment variable
* GEOGRAPHICLIB_MAGNETIC_NAME, if set, otherwise, it is "wmm2010".
* The MagneticModel class does not use this function; it is just
* provided as a convenience for a calling program when constructing a
* MagneticModel object.
**********************************************************************/
static System::String^ DefaultMagneticName();
};
} //namespace NETGeographicLib
|
