GeographicLib  2.1.1
MagneticField.cpp
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1 /**
2  * \file MagneticField.cpp
3  * \brief Command line utility for evaluating magnetic fields
4  *
5  * Copyright (c) Charles Karney (2011-2022) <charles@karney.com> and licensed
6  * under the MIT/X11 License. For more information, see
7  * https://geographiclib.sourceforge.io/
8  *
9  * See the <a href="MagneticField.1.html">man page</a> for usage information.
10  **********************************************************************/
11 
12 #include <iostream>
13 #include <string>
14 #include <sstream>
15 #include <fstream>
18 #include <GeographicLib/DMS.hpp>
20 
21 #if defined(_MSC_VER)
22 // Squelch warnings about constant conditional and enum-float expressions
23 # pragma warning (disable: 4127 5055)
24 #endif
25 
26 #include "MagneticField.usage"
27 
28 int main(int argc, const char* const argv[]) {
29  try {
30  using namespace GeographicLib;
31  typedef Math::real real;
33  bool verbose = false, longfirst = false;
34  std::string dir;
35  std::string model = MagneticModel::DefaultMagneticName();
36  std::string istring, ifile, ofile, cdelim;
37  char lsep = ';';
38  real time = 0, lat = 0, h = 0;
39  bool timeset = false, circle = false, rate = false;
40  real hguard = 500000, tguard = 50;
41  int prec = 1, Nmax = -1, Mmax = -1;
42 
43  for (int m = 1; m < argc; ++m) {
44  std::string arg(argv[m]);
45  if (arg == "-n") {
46  if (++m == argc) return usage(1, true);
47  model = argv[m];
48  } else if (arg == "-d") {
49  if (++m == argc) return usage(1, true);
50  dir = argv[m];
51  } else if (arg == "-N") {
52  if (++m == argc) return usage(1, true);
53  try {
54  Nmax = Utility::val<int>(std::string(argv[m]));
55  if (Nmax < 0) {
56  std::cerr << "Maximum degree " << argv[m] << " is negative\n";
57  return 1;
58  }
59  }
60  catch (const std::exception&) {
61  std::cerr << "Precision " << argv[m] << " is not a number\n";
62  return 1;
63  }
64  } else if (arg == "-M") {
65  if (++m == argc) return usage(1, true);
66  try {
67  Mmax = Utility::val<int>(std::string(argv[m]));
68  if (Mmax < 0) {
69  std::cerr << "Maximum order " << argv[m] << " is negative\n";
70  return 1;
71  }
72  }
73  catch (const std::exception&) {
74  std::cerr << "Precision " << argv[m] << " is not a number\n";
75  return 1;
76  }
77  } else if (arg == "-t") {
78  if (++m == argc) return usage(1, true);
79  try {
80  time = Utility::fractionalyear<real>(std::string(argv[m]));
81  timeset = true;
82  circle = false;
83  }
84  catch (const std::exception& e) {
85  std::cerr << "Error decoding argument of " << arg << ": "
86  << e.what() << "\n";
87  return 1;
88  }
89  } else if (arg == "-c") {
90  if (m + 3 >= argc) return usage(1, true);
91  try {
92  using std::fabs;
93  time = Utility::fractionalyear<real>(std::string(argv[++m]));
94  DMS::flag ind;
95  lat = DMS::Decode(std::string(argv[++m]), ind);
96  if (ind == DMS::LONGITUDE)
97  throw GeographicErr("Bad hemisphere letter on latitude");
98  if (!(fabs(lat) <= Math::qd))
99  throw GeographicErr("Latitude not in [-" + std::to_string(Math::qd)
100  + "d, " + std::to_string(Math::qd) + "d]");
101  h = Utility::val<real>(std::string(argv[++m]));
102  timeset = false;
103  circle = true;
104  }
105  catch (const std::exception& e) {
106  std::cerr << "Error decoding argument of " << arg << ": "
107  << e.what() << "\n";
108  return 1;
109  }
110  } else if (arg == "-r")
111  rate = !rate;
112  else if (arg == "-w")
113  longfirst = !longfirst;
114  else if (arg == "-p") {
115  if (++m == argc) return usage(1, true);
116  try {
117  prec = Utility::val<int>(std::string(argv[m]));
118  }
119  catch (const std::exception&) {
120  std::cerr << "Precision " << argv[m] << " is not a number\n";
121  return 1;
122  }
123  } else if (arg == "-T") {
124  if (++m == argc) return usage(1, true);
125  try {
126  tguard = Utility::val<real>(std::string(argv[m]));
127  }
128  catch (const std::exception& e) {
129  std::cerr << "Error decoding argument of " << arg << ": "
130  << e.what() << "\n";
131  return 1;
132  }
133  } else if (arg == "-H") {
134  if (++m == argc) return usage(1, true);
135  try {
136  hguard = Utility::val<real>(std::string(argv[m]));
137  }
138  catch (const std::exception& e) {
139  std::cerr << "Error decoding argument of " << arg << ": "
140  << e.what() << "\n";
141  return 1;
142  }
143  } else if (arg == "-v")
144  verbose = true;
145  else if (arg == "--input-string") {
146  if (++m == argc) return usage(1, true);
147  istring = argv[m];
148  } else if (arg == "--input-file") {
149  if (++m == argc) return usage(1, true);
150  ifile = argv[m];
151  } else if (arg == "--output-file") {
152  if (++m == argc) return usage(1, true);
153  ofile = argv[m];
154  } else if (arg == "--line-separator") {
155  if (++m == argc) return usage(1, true);
156  if (std::string(argv[m]).size() != 1) {
157  std::cerr << "Line separator must be a single character\n";
158  return 1;
159  }
160  lsep = argv[m][0];
161  } else if (arg == "--comment-delimiter") {
162  if (++m == argc) return usage(1, true);
163  cdelim = argv[m];
164  } else if (arg == "--version") {
165  std::cout << argv[0] << ": GeographicLib version "
166  << GEOGRAPHICLIB_VERSION_STRING << "\n";
167  return 0;
168  } else {
169  int retval = usage(!(arg == "-h" || arg == "--help"), arg != "--help");
170  if (arg == "-h")
171  std::cout<< "\nDefault magnetic path = \""
173  << "\"\nDefault magnetic name = \""
175  << "\"\n";
176  return retval;
177  }
178  }
179 
180  if (!ifile.empty() && !istring.empty()) {
181  std::cerr << "Cannot specify --input-string and --input-file together\n";
182  return 1;
183  }
184  if (ifile == "-") ifile.clear();
185  std::ifstream infile;
186  std::istringstream instring;
187  if (!ifile.empty()) {
188  infile.open(ifile.c_str());
189  if (!infile.is_open()) {
190  std::cerr << "Cannot open " << ifile << " for reading\n";
191  return 1;
192  }
193  } else if (!istring.empty()) {
194  std::string::size_type m = 0;
195  while (true) {
196  m = istring.find(lsep, m);
197  if (m == std::string::npos)
198  break;
199  istring[m] = '\n';
200  }
201  instring.str(istring);
202  }
203  std::istream* input = !ifile.empty() ? &infile :
204  (!istring.empty() ? &instring : &std::cin);
205 
206  std::ofstream outfile;
207  if (ofile == "-") ofile.clear();
208  if (!ofile.empty()) {
209  outfile.open(ofile.c_str());
210  if (!outfile.is_open()) {
211  std::cerr << "Cannot open " << ofile << " for writing\n";
212  return 1;
213  }
214  }
215  std::ostream* output = !ofile.empty() ? &outfile : &std::cout;
216 
217  using std::fmax;
218  tguard = fmax(real(0), tguard);
219  hguard = fmax(real(0), hguard);
220  prec = std::min(10 + Math::extra_digits(), std::max(0, prec));
221  int retval = 0;
222  try {
223  using std::isfinite;
224  const MagneticModel m(model, dir, Geocentric::WGS84(), Nmax, Mmax);
225  if ((timeset || circle)
226  && (!isfinite(time) ||
227  time < m.MinTime() - tguard ||
228  time > m.MaxTime() + tguard))
229  throw GeographicErr("Time " + Utility::str(time) +
230  " too far outside allowed range [" +
231  Utility::str(m.MinTime()) + "," +
232  Utility::str(m.MaxTime()) + "]");
233  if (circle
234  && (!isfinite(h) ||
235  h < m.MinHeight() - hguard ||
236  h > m.MaxHeight() + hguard))
237  throw GeographicErr("Height " + Utility::str(h/1000) +
238  "km too far outside allowed range [" +
239  Utility::str(m.MinHeight()/1000) + "km," +
240  Utility::str(m.MaxHeight()/1000) + "km]");
241  if (verbose) {
242  std::cerr << "Magnetic file: " << m.MagneticFile() << "\n"
243  << "Name: " << m.MagneticModelName() << "\n"
244  << "Description: " << m.Description() << "\n"
245  << "Date & Time: " << m.DateTime() << "\n"
246  << "Time range: ["
247  << m.MinTime() << ","
248  << m.MaxTime() << "]\n"
249  << "Height range: ["
250  << m.MinHeight()/1000 << "km,"
251  << m.MaxHeight()/1000 << "km]\n";
252  }
253  if ((timeset || circle) && (time < m.MinTime() || time > m.MaxTime()))
254  std::cerr << "WARNING: Time " << time
255  << " outside allowed range ["
256  << m.MinTime() << "," << m.MaxTime() << "]\n";
257  if (circle && (h < m.MinHeight() || h > m.MaxHeight()))
258  std::cerr << "WARNING: Height " << h/1000
259  << "km outside allowed range ["
260  << m.MinHeight()/1000 << "km,"
261  << m.MaxHeight()/1000 << "km]\n";
262  const MagneticCircle c(circle ? m.Circle(time, lat, h) :
263  MagneticCircle());
264  std::string s, eol, stra, strb;
265  std::istringstream str;
266  while (std::getline(*input, s)) {
267  try {
268  eol = "\n";
269  if (!cdelim.empty()) {
270  std::string::size_type n = s.find(cdelim);
271  if (n != std::string::npos) {
272  eol = " " + s.substr(n) + "\n";
273  s = s.substr(0, n);
274  }
275  }
276  str.clear(); str.str(s);
277  if (!(timeset || circle)) {
278  if (!(str >> stra))
279  throw GeographicErr("Incomplete input: " + s);
280  time = Utility::fractionalyear<real>(stra);
281  if (time < m.MinTime() - tguard || time > m.MaxTime() + tguard)
282  throw GeographicErr("Time " + Utility::str(time) +
283  " too far outside allowed range [" +
284  Utility::str(m.MinTime()) + "," +
285  Utility::str(m.MaxTime()) +
286  "]");
287  if (time < m.MinTime() || time > m.MaxTime())
288  std::cerr << "WARNING: Time " << time
289  << " outside allowed range ["
290  << m.MinTime() << "," << m.MaxTime() << "]\n";
291  }
292  real lon;
293  if (circle) {
294  if (!(str >> strb))
295  throw GeographicErr("Incomplete input: " + s);
296  DMS::flag ind;
297  lon = DMS::Decode(strb, ind);
298  if (ind == DMS::LATITUDE)
299  throw GeographicErr("Bad hemisphere letter on " + strb);
300  } else {
301  if (!(str >> stra >> strb))
302  throw GeographicErr("Incomplete input: " + s);
303  DMS::DecodeLatLon(stra, strb, lat, lon, longfirst);
304  h = 0; // h is optional
305  if (str >> h) {
306  if (h < m.MinHeight() - hguard || h > m.MaxHeight() + hguard)
307  throw GeographicErr("Height " + Utility::str(h/1000) +
308  "km too far outside allowed range [" +
309  Utility::str(m.MinHeight()/1000) + "km," +
310  Utility::str(m.MaxHeight()/1000) + "km]");
311  if (h < m.MinHeight() || h > m.MaxHeight())
312  std::cerr << "WARNING: Height " << h/1000
313  << "km outside allowed range ["
314  << m.MinHeight()/1000 << "km,"
315  << m.MaxHeight()/1000 << "km]\n";
316  }
317  else
318  str.clear();
319  }
320  if (str >> stra)
321  throw GeographicErr("Extra junk in input: " + s);
322  real bx, by, bz, bxt, byt, bzt;
323  if (circle)
324  c(lon, bx, by, bz, bxt, byt, bzt);
325  else
326  m(time, lat, lon, h, bx, by, bz, bxt, byt, bzt);
327  real H, F, D, I, Ht, Ft, Dt, It;
328  MagneticModel::FieldComponents(bx, by, bz, bxt, byt, bzt,
329  H, F, D, I, Ht, Ft, Dt, It);
330 
331  *output << DMS::Encode(D, prec + 1, DMS::NUMBER) << " "
332  << DMS::Encode(I, prec + 1, DMS::NUMBER) << " "
333  << Utility::str(H, prec) << " "
334  << Utility::str(by, prec) << " "
335  << Utility::str(bx, prec) << " "
336  << Utility::str(-bz, prec) << " "
337  << Utility::str(F, prec) << eol;
338  if (rate)
339  *output << DMS::Encode(Dt, prec + 1, DMS::NUMBER) << " "
340  << DMS::Encode(It, prec + 1, DMS::NUMBER) << " "
341  << Utility::str(Ht, prec) << " "
342  << Utility::str(byt, prec) << " "
343  << Utility::str(bxt, prec) << " "
344  << Utility::str(-bzt, prec) << " "
345  << Utility::str(Ft, prec) << eol;
346  }
347  catch (const std::exception& e) {
348  *output << "ERROR: " << e.what() << "\n";
349  retval = 1;
350  }
351  }
352  }
353  catch (const std::exception& e) {
354  std::cerr << "Error reading " << model << ": " << e.what() << "\n";
355  retval = 1;
356  }
357  return retval;
358  }
359  catch (const std::exception& e) {
360  std::cerr << "Caught exception: " << e.what() << "\n";
361  return 1;
362  }
363  catch (...) {
364  std::cerr << "Caught unknown exception\n";
365  return 1;
366  }
367 }
Header for GeographicLib::DMS class.
GeographicLib::Math::real real
Definition: GeodSolve.cpp:31
Header for GeographicLib::MagneticCircle class.
int main(int argc, const char *const argv[])
Header for GeographicLib::MagneticModel class.
Header for GeographicLib::Utility class.
static std::string Encode(real angle, component trailing, unsigned prec, flag ind=NONE, char dmssep=char(0))
Definition: DMS.cpp:416
static void DecodeLatLon(const std::string &dmsa, const std::string &dmsb, real &lat, real &lon, bool longfirst=false)
Definition: DMS.cpp:368
static Math::real Decode(const std::string &dms, flag &ind)
Definition: DMS.cpp:40
static const Geocentric & WGS84()
Definition: Geocentric.cpp:31
Exception handling for GeographicLib.
Definition: Constants.hpp:316
Geomagnetic field on a circle of latitude.
Model of the earth's magnetic field.
const std::string & DateTime() const
MagneticCircle Circle(real t, real lat, real h) const
static std::string DefaultMagneticPath()
const std::string & Description() const
Math::real MaxHeight() const
const std::string & MagneticFile() const
static std::string DefaultMagneticName()
Math::real MinHeight() const
const std::string & MagneticModelName() const
static void FieldComponents(real Bx, real By, real Bz, real &H, real &F, real &D, real &I)
@ qd
degrees per quarter turn
Definition: Math.hpp:141
static int extra_digits()
Definition: Math.cpp:51
static int set_digits(int ndigits=0)
Definition: Utility.cpp:184
static std::string str(T x, int p=-1)
Definition: Utility.hpp:161
Namespace for GeographicLib.
Definition: Accumulator.cpp:12