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Geod3ODE.cpp
Go to the documentation of this file.
/**
* \file Geod3ODE.cpp
* \brief Command line utility for using an ODE solver for geodesics on a
* triaxial ellipsoid
*
* Copyright (c) Charles Karney (2024-2025) <karney@alum.mit.edu> and licensed
* under the MIT/X11 License. For more information, see
* https://geographiclib.sourceforge.io/
*
* Use "Geod3ODE --help" for brief documentation.
**********************************************************************/
#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>
#include <fstream>
#include <GeographicLib/Math.hpp>
#include <GeographicLib/DMS.hpp>
#include <GeographicLib/Utility.hpp>
#include <GeographicLib/Angle.hpp>
#if defined(_MSC_VER)
// Squelch warning triggered by boost:
// 4127: conditional expression is constant
# pragma warning (disable: 4127)
#endif
#include "TriaxialGeodesicODE.hpp"
// #include "GeodSolve.usage"
using real = GeographicLib::Math::real;
using ang = GeographicLib::Angle;
std::string ErrorString(real err, int prec) {
std::ostringstream s;
s << std::scientific << std::setprecision(prec) << err;
return s.str();
}
int usage(int retval, bool /*brief*/) {
(retval ? std::cerr : std:: cout ) << "Usage:\n"
"\n"
" This implements some of the functionality of Geod3Solve(1) by integrating the\n"
" ordinary differential equations for the geodesic. Only direct geodesic\n"
" calculations are supported.\n"
"\n"
" The following options of Geod3Solve(1) are supported\n"
" -t a b c | -e b e2 k2 kp2 \n"
" -L bet1 omg1 alp1\n"
" -u\n"
" -d | -:\n"
" -w \n"
" -f\n"
" -p prec\n"
"\n"
" The following options of Geod3Solve(1) are not supported\n"
" -i\n"
" -e2\n"
" -u\n"
"\n"
" The following are new options\n"
"\n"
" -b\n"
" bufferd mode (only useful with the -L option). Causes all the s12 values\n"
" to be buffered and fed into the integrator at the end. This sorts the\n"
" entries so that the integrator doesn't have to the continually restarted.\n"
"\n"
" -x\n"
" extended mode. Computes and prints the reduced length, m12, and the\n"
" geodesic scales, M12, M21.\n"
"\n"
" --eps eps\n"
" sets the eps parameter in the constructor for TriaxialGeodesicODE.\n"
"\n"
" --dense\n"
" use the dense solver allowing interpolated way points to be computed\n"
" inexpensively.\n"
"\n"
" --normp\n"
" force the solution vector onto the ellipsoid when computing the\n"
" acceleration.\n"
"\n"
" --errors\n"
" print error estimates, the distance from the ellipsoid (in meters) and\n"
" the deviation of the velocity from a unit tangential vector.\n"
"\n"
" --steps\n"
" print the number of integration steps and the number of times the\n"
" acceleration was computed.\n";
return retval;
}
int main(int argc, const char* const argv[]) {
try {
using namespace GeographicLib;
using namespace Triaxial;
using namespace experimental;
Utility::set_digits();
bool dms = false, longfirst = false,
linecalc = false, extended = false, dense = false, normp = false,
buffered = false, full = false, errors = false, steps = false;
real
a = Constants::Triaxial_Earth_a(),
b = Constants::Triaxial_Earth_b(),
c = Constants::Triaxial_Earth_c(),
e2 = -1, k2 = 0, kp2 = 0, eps = 0;
ang bet1 = ang(0), omg1 = ang(0), alp1 = ang(0), bet2, omg2, alp2;
real s12, m12, M12, M21;
std::vector<real> s12v;
int prec = 3;
std::string istring, ifile, ofile, cdelim;
char lsep = ';', dmssep = char(0);
for (int m = 1; m < argc; ++m) {
std::string arg(argv[m]);
if (arg == "-t") {
if (m + 3 >= argc) return usage(1, true);
try {
a = Utility::val<real>(std::string(argv[m + 1]));
b = Utility::val<real>(std::string(argv[m + 2]));
c = Utility::val<real>(std::string(argv[m + 3]));
}
catch (const std::exception& e) {
std::cerr << "Error decoding arguments of -t: " << e.what() << "\n";
return 1;
}
e2 = -1;
m += 3;
} else if (arg == "-e") {
// Cayley ellipsoid sqrt([2,1,1/2]) is
// -e 1 3/2 1 2
if (m + 4 >= argc) return usage(1, true);
try {
b = Utility::val<real>(std::string(argv[m + 1]));
e2 = Utility::fract<real>(std::string(argv[m + 2]));
k2 = Utility::fract<real>(std::string(argv[m + 3]));
kp2 = Utility::fract<real>(std::string(argv[m + 4]));
}
catch (const std::exception& e) {
std::cerr << "Error decoding arguments of -e: " << e.what() << "\n";
return 1;
}
a = -1;
m += 4;
} else if (arg == "-x")
extended = true;
else if (arg == "-L") {
linecalc = true;
if (m + 3 >= argc) return usage(1, true);
try {
ang::DecodeLatLon(std::string(argv[m + 1]),
std::string(argv[m + 2]),
bet1, omg1, longfirst);
alp1 = ang::DecodeAzimuth(std::string(argv[m + 3]));
}
catch (const std::exception& e) {
std::cerr << "Error decoding arguments of -L: " << e.what() << "\n";
return 1;
}
m += 3;
} else if (arg == "--eps") {
if (m + 1 >= argc) return usage(1, true);
try {
using std::pow;
eps = pow(std::numeric_limits<real>::epsilon(),
Utility::fract<real>(std::string(argv[m + 1])));
}
catch (const std::exception& e) {
std::cerr << "Error decoding argument of --eps: " << e.what() << "\n";
return 1;
}
m += 1;
} else if (arg == "--dense")
dense = true;
else if (arg == "--normp")
normp = true;
else if (arg == "--errors")
errors = true;
else if (arg == "--steps")
steps = true;
else if (arg == "-b")
buffered = true;
else if (arg == "-f")
full = true;
else if (arg == "-d") {
dms = true;
dmssep = '\0';
} else if (arg == "-:") {
dms = true;
dmssep = ':';
} else if (arg == "-w")
longfirst = !longfirst;
else if (arg == "-p") {
if (++m == argc) return usage(1, true);
try {
prec = Utility::val<int>(std::string(argv[m]));
}
catch (const std::exception&) {
std::cerr << "Precision " << argv[m] << " is not a number\n";
return 1;
}
} else if (arg == "--input-string") {
if (++m == argc) return usage(1, true);
istring = argv[m];
} else if (arg == "--input-file") {
if (++m == argc) return usage(1, true);
ifile = argv[m];
} else if (arg == "--output-file") {
if (++m == argc) return usage(1, true);
ofile = argv[m];
} else if (arg == "--line-separator") {
if (++m == argc) return usage(1, true);
if (std::string(argv[m]).size() != 1) {
std::cerr << "Line separator must be a single character\n";
return 1;
}
lsep = argv[m][0];
} else if (arg == "--comment-delimiter") {
if (++m == argc) return usage(1, true);
cdelim = argv[m];
} else if (arg == "--version") {
std::cout << argv[0] << ": GeographicLib version "
<< GEOGRAPHICLIB_VERSION_STRING << "\n";
return 0;
} else
return usage(!(arg == "-h" || arg == "--help"), arg != "--help");
}
Ellipsoid3 t(e2 >= 0 ? Ellipsoid3(b, e2, k2, kp2) : Ellipsoid3(a, b, c));
if (!ifile.empty() && !istring.empty()) {
std::cerr << "Cannot specify --input-string and --input-file together\n";
return 1;
}
if (ifile == "-") ifile.clear();
std::ifstream infile;
std::istringstream instring;
if (!ifile.empty()) {
infile.open(ifile.c_str());
if (!infile.is_open()) {
std::cerr << "Cannot open " << ifile << " for reading\n";
return 1;
}
} else if (!istring.empty()) {
std::string::size_type m = 0;
while (true) {
m = istring.find(lsep, m);
if (m == std::string::npos)
break;
istring[m] = '\n';
}
instring.str(istring);
}
std::istream* input = !ifile.empty() ? &infile :
(!istring.empty() ? &instring : &std::cin);
std::ofstream outfile;
if (ofile == "-") ofile.clear();
if (!ofile.empty()) {
outfile.open(ofile.c_str());
if (!outfile.is_open()) {
std::cerr << "Cannot open " << ofile << " for writing\n";
return 1;
}
}
std::ostream* output = !ofile.empty() ? &outfile : &std::cout;
using std::round, std::log10;
int disprec = int(round(log10(6400000/b)));
// Max precision = 10: 0.1 nm in distance, 10^-15 deg (= 0.11 nm),
// 10^-11 sec (= 0.3 nm).
prec = std::min(10 + Math::extra_digits(), std::max(0, prec));
std::string s, eol, sbet1, somg1, salp1, sbet2, somg2, salp2, ss12, strc;
std::istringstream str;
int retval = 0;
buffered = buffered && linecalc;
errors = errors && !buffered;
TriaxialGeodesicODE l = linecalc ?
TriaxialGeodesicODE(t, bet1, omg1, alp1, extended, dense, normp, eps) :
TriaxialGeodesicODE(t, extended, dense, normp, eps);
while (std::getline(*input, s)) {
try {
eol = "\n";
if (!cdelim.empty()) {
std::string::size_type m = s.find(cdelim);
if (m != std::string::npos) {
eol = " " + s.substr(m) + "\n";
s = s.substr(0, m);
}
}
str.clear(); str.str(s);
if (!(linecalc ? (str >> ss12) :
(str >> sbet1 >> somg1 >> salp1 >> ss12)))
throw GeographicErr("Incomplete input: " + s);
if (str >> strc)
throw GeographicErr("Extraneious input: " + s);
s12 = Utility::val<real>(ss12);
if (linecalc) {
if (buffered) s12v.push_back(s12);
} else {
ang::DecodeLatLon(sbet1, somg1, bet1, omg1, longfirst);
alp1 = ang::DecodeAzimuth(salp1);
l.Reset(bet1, omg1, alp1);
}
if (!buffered) {
auto errs = l.Position(s12, bet2, omg2, alp2, m12, M12, M21);
if (full)
*output << ang::LatLonString(bet1, omg1, prec, dms, dmssep,
longfirst) << " "
<< ang::AzimuthString(alp1, prec, dms, dmssep) << " ";
*output << ang::LatLonString(bet2, omg2, prec, dms, dmssep,
longfirst) << " "
<< ang::AzimuthString(alp2, prec, dms, dmssep);
if (full)
*output << " " << Utility::str(s12, prec + disprec);
if (extended)
*output << " " << Utility::str(m12, prec + disprec)
<< " " << Utility::str(M12, prec+7)
<< " " << Utility::str(M21, prec+7);
if (steps)
*output << " " << l.NSteps() << " " << l.IntSteps();
if (errors)
*output << " " << ErrorString(errs.first, 2)
<< " " << ErrorString(errs.second, 2);
*output << eol;
}
}
catch (const std::exception& e) {
if (buffered)
s12v.push_back(Math::NaN());
else
// Write error message cout so output lines match input lines
*output << "ERROR: " << e.what() << " " << s << "\n";
retval = 1;
}
}
if (buffered) {
std::vector<ang> bet2v, omg2v, alp2v;
std::vector<real> m12v, M12v, M21v;
l.Position(s12v, bet2v, omg2v, alp2v, m12v, M12v, M21v);
for (size_t i = 0; i < s12v.size(); ++i) {
if (full)
*output << ang::LatLonString(bet1, omg1, prec, dms, dmssep,
longfirst) << " "
<< ang::AzimuthString(alp1, prec, dms, dmssep) << " ";
*output << ang::LatLonString(bet2v[i], omg2v[i], prec, dms, dmssep,
longfirst) << " "
<< ang::AzimuthString(alp2v[i], prec, dms, dmssep);
if (full)
*output << " " << Utility::str(s12v[i], prec + disprec);
if (extended)
*output << " " << Utility::str(m12v[i], prec + disprec)
<< " " << Utility::str(M12v[i], prec+7)
<< " " << Utility::str(M21v[i], prec+7);
*output << eol;
}
}
return retval;
}
catch (const std::exception& e) {
std::cerr << "Caught exception: " << e.what() << "\n";
return 1;
}
catch (...) {
std::cerr << "Caught unknown exception\n";
return 1;
}
}
Angle.hpp
Header for the GeographicLib::AngleT class.
DMS.hpp
Header for GeographicLib::DMS class.
usage
int usage(int retval, bool)
Definition Geod3ODE.cpp:41
ErrorString
std::string ErrorString(real err, int prec)
Definition Geod3ODE.cpp:35
main
int main(int argc, const char *const argv[])
Definition Geod3ODE.cpp:94
ang
GeographicLib::Angle ang
Definition Geod3Solve.cpp:26
real
GeographicLib::Math::real real
Definition Geod3Solve.cpp:25
Math.hpp
Header for GeographicLib::Math class.
TriaxialGeodesicODE.hpp
Header for GeographicLib::Triaxial class.
Utility.hpp
Header for GeographicLib::Utility class.
GeographicLib::AngleT< Math::real >::DecodeLatLon
static void DecodeLatLon(const std::string &stra, const std::string &strb, AngleT &lat, AngleT &lon, bool longfirst=false)
GeographicLib::AngleT< Math::real >::LatLonString
static std::string LatLonString(AngleT lat, AngleT lon, int prec, bool dms=false, char dmssep='\0', bool longfirst=false)
GeographicLib::AngleT< Math::real >::DecodeAzimuth
static AngleT DecodeAzimuth(const std::string &azistr)
GeographicLib::AngleT< Math::real >::AzimuthString
static std::string AzimuthString(AngleT azi, int prec, bool dms=false, char dmssep='\0')
GeographicLib::Constants::Triaxial_Earth_b
static T Triaxial_Earth_b()
Definition Constants.hpp:218
GeographicLib::Constants::Triaxial_Earth_a
static T Triaxial_Earth_a()
Definition Constants.hpp:211
GeographicLib::Constants::Triaxial_Earth_c
static T Triaxial_Earth_c()
Definition Constants.hpp:225
GeographicLib::GeographicErr
Exception handling for GeographicLib.
Definition Constants.hpp:344
GeographicLib::Math::NaN
static T NaN()
Definition Math.cpp:301
GeographicLib::Math::real
double real
Definition Math.hpp:115
GeographicLib::Math::extra_digits
static int extra_digits()
Definition Math.cpp:49
GeographicLib::Utility::fract
static T fract(const std::string &s)
Definition Utility.hpp:298
GeographicLib::Utility::val
static T val(const std::string &s)
Definition Utility.hpp:225
GeographicLib::Utility::set_digits
static int set_digits(int ndigits=0)
Definition Utility.cpp:184
GeographicLib::Utility::str
static std::string str(T x, int p=-1)
Definition Utility.hpp:161
GeographicLib::Triaxial
Namespace for operations on triaxial ellipsoids.
Definition Cartesian3.cpp:13
GeographicLib::experimental
Namespace for experimental components of GeographicLib.
Definition TriaxialGeodesicODE.hpp:66
GeographicLib
Namespace for GeographicLib.
Definition Accumulator.cpp:12
GeographicLib::Angle
AngleT< Math::real > Angle
Definition Angle.hpp:760