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Geod3Solve.cpp
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/**
* \file Geod3Solve.cpp
* \brief Command line utility for computing 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/
*
* See the <a href="Geod3Solve.1.html">man page</a> for usage information.
**********************************************************************/
#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>
#include <GeographicLib/Triaxial/Geodesic3.hpp>
#include "Geod3Solve.usage"
using real = GeographicLib::Math::real;
using ang = GeographicLib::Angle;
void BiaxialCoords(bool fwd, real f, ang& bet, ang& omg) {
using std::isnan, std::signbit;
if (isnan(f)) return;
// fwd: biaxial -> triaxial
// !fwd: triaxial -> biaxial
if (fwd)
bet = bet.modang(1 - f);
if (signbit(f)) {
omg -= ang::cardinal(1);
std::swap(bet, omg);
omg += ang::cardinal(1);
}
if (!fwd)
bet = bet.modang(1 / (1 - f));
}
void BiaxialCoords(bool fwd, real f, ang& bet, ang& omg, ang& alp) {
using std::isnan, std::signbit;
if (isnan(f)) return;
// fwd: biaxial -> triaxial
// !fwd: triaxial -> biaxial
BiaxialCoords(fwd, f, bet, omg);
if (signbit(f)) alp.reflect(false, false, true);
}
int main(int argc, const char* const argv[]) {
try {
using namespace GeographicLib;
using namespace Triaxial;
using std::signbit, std::isnan, std::fabs;
Utility::set_digits();
bool inverse = false,
dms = false, full = false, unroll = false,
longfirst = false,
linecalc = false;
real
a = Constants::Triaxial_Earth_a(),
b = Constants::Triaxial_Earth_b(),
c = Constants::Triaxial_Earth_c(),
// Markers to determine how the ellipsoid is specified
e2 = -1, f = Math::NaN(), k2 = 0, kp2 = 0;
ang bet1, omg1, alp1, bet2, omg2, alp2;
real s12;
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 == "-i") {
inverse = true;
linecalc = false;
} else 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;
}
f = Math::NaN(); e2 = -1;
m += 3;
} else if (arg == "-e") {
// Cayley ellipsoid sqrt([2,1,1/2]) is
// -e 1 3/2 1/3 2/3
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; f = Math::NaN();
m += 4;
} else if (arg == "-e2") {
if (m + 2 >= argc) return usage(1, true);
try {
b = Utility::val<real>(std::string(argv[m + 1]));
f = Utility::fract<real>(std::string(argv[m + 2]));
}
// f > 0, k2 = 1, kp2 = 0
// a = b; c = b * (1 - f)
// e2 = factor(subst([a = A, b = A, c = A*(1-f)],(a^2 - c^2)/b^2))
// = f * (2 - f)
// f < 0, k2 = 0, kp2 = 1
// a = A * (1 - f); c = b
// e2 = factor(subst([a = A*(1-f), b = A, c = A],(a^2 - c^2)/b^2))
// = -f * (2 - f)
catch (const std::exception& e) {
std::cerr << "Error decoding arguments of -e2: " << e.what() << "\n";
return 1;
}
a = e2 = -1;
m += 2;
} else if (arg == "-L") {
linecalc = true;
inverse = false;
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 == "-u")
unroll = true;
else if (arg == "-d") {
dms = true;
dmssep = '\0';
} else if (arg == "-:") {
dms = true;
dmssep = ':';
} else if (arg == "-w")
longfirst = !longfirst;
else if (arg == "-f")
full = true;
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");
}
Geodesic3 t = e2 >= 0 ? Geodesic3(b, e2, k2, kp2) :
!isnan(f) ? Geodesic3(b, fabs(f) * (2 - f),
signbit(f) ? 0 : 1, signbit(f) ? 1 : 0) :
Geodesic3(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;
if (linecalc) {
BiaxialCoords(true, f, bet1, omg1, alp1);
}
std::unique_ptr<GeodesicLine3> lp = linecalc ?
std::make_unique<GeodesicLine3>(t, bet1, omg1, alp1) : nullptr;
// 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));
using std::round, std::log10, std::ceil;
int disprec = std::max(0, prec + int(round(log10(6400000/b)))),
angprec = prec + 5;
std::string s, eol, sbet1, somg1, salp1, sbet2, somg2, salp2, ss12, strc;
std::istringstream str;
int retval = 0;
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 (inverse) {
if (!(str >> sbet1 >> somg1 >> sbet2 >> somg2))
throw GeographicErr("Incomplete input: " + s);
if (str >> strc)
throw GeographicErr("Extraneous input: " + strc);
ang::DecodeLatLon(sbet1, somg1, bet1, omg1, longfirst);
ang::DecodeLatLon(sbet2, somg2, bet2, omg2, longfirst);
BiaxialCoords(true, f, bet1, omg1);
BiaxialCoords(true, f, bet2, omg2);
GeodesicLine3 l = t.Inverse(bet1, omg1, bet2, omg2,
s12, alp1, alp2);
if (unroll && full) {
l.Position(s12, bet2, omg2, alp2);
}
BiaxialCoords(false, f, bet1, omg1, alp1);
BiaxialCoords(false, f, bet2, omg2, alp2);
if (full)
*output << ang::LatLonString(bet1, omg1,
angprec, dms, dmssep, longfirst)
<< " " << ang::AzimuthString(alp1, angprec, dms, dmssep)
<< " "
<< ang::LatLonString(bet2, omg2,
angprec, dms, dmssep, longfirst)
<< " " << ang::AzimuthString(alp2, angprec, dms, dmssep)
<< " "
<< Utility::str(s12, disprec) << eol;
else
*output << ang::AzimuthString(alp1, angprec, dms, dmssep) << " "
<< ang::AzimuthString(alp2, angprec, dms, dmssep) << " "
<< Utility::str(s12, disprec) << eol;
} else {
if (linecalc) {
if (!(str >> ss12))
throw GeographicErr("Incomplete input: " + s);
} else {
if (!(str >> sbet1 >> somg1 >> salp1 >> ss12))
throw GeographicErr("Incomplete input: " + s);
}
if (str >> strc)
throw GeographicErr("Extraneous input: " + strc);
s12 = Utility::val<real>(ss12);
if (linecalc)
lp->Position(s12, bet2, omg2, alp2);
else {
ang::DecodeLatLon(sbet1, somg1, bet1, omg1, longfirst);
alp1 = ang::DecodeAzimuth(salp1);
BiaxialCoords(true, f, bet1, omg1, alp1);
t.Direct(bet1, omg1, alp1, s12, bet2, omg2, alp2);
}
if (!unroll) {
Ellipsoid3::AngNorm(bet2, omg2, alp2, !isnan(f) && signbit(f));
bet2 = bet2.base();
omg2 = omg2.base();
alp2 = alp2.base();
}
BiaxialCoords(false, f, bet1, omg1, alp1);
BiaxialCoords(false, f, bet2, omg2, alp2);
if (full)
*output << ang::LatLonString(bet1, omg1,
angprec, dms, dmssep, longfirst)
<< " " << ang::AzimuthString(alp1, angprec, dms, dmssep)
<< " "
<< ang::LatLonString(bet2, omg2,
angprec, dms, dmssep, longfirst)
<< " " << ang::AzimuthString(alp2, angprec, dms, dmssep)
<< " "
<< Utility::str(s12, disprec) << eol;
else
*output << ang::LatLonString(bet2, omg2,
angprec, dms, dmssep, longfirst)
<< " "
<< ang::AzimuthString(alp2, angprec, dms, dmssep) << eol;
}
}
catch (const std::exception& e) {
// Write error message cout so output lines match input lines
*output << "ERROR: " << e.what() << "\n";
retval = 1;
}
}
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
main
int main(int argc, const char *const argv[])
Definition Geod3Solve.cpp:53
ang
GeographicLib::Angle ang
Definition Geod3Solve.cpp:26
BiaxialCoords
void BiaxialCoords(bool fwd, real f, ang &bet, ang &omg)
Definition Geod3Solve.cpp:28
real
GeographicLib::Math::real real
Definition Geod3Solve.cpp:25
Geodesic3.hpp
Header for GeographicLib::Triaxial::Geodesic3 class.
Math.hpp
Header for GeographicLib::Math class.
Utility.hpp
Header for GeographicLib::Utility class.
GeographicLib::AngleT::base
AngleT base() const
Definition Angle.hpp:642
GeographicLib::AngleT< Math::real >::cardinal
static AngleT cardinal(Math::real q)
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::modang
AngleT modang(T m) const
Definition Angle.hpp:711
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::AngleT::reflect
AngleT & reflect(bool flips, bool flipc=false, bool swapp=false)
Definition Angle.hpp:696
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
Namespace for GeographicLib.
Definition Accumulator.cpp:12
GeographicLib::Angle
AngleT< Math::real > Angle
Definition Angle.hpp:760
std::swap
void swap(GeographicLib::NearestNeighbor< dist_t, pos_t, distfun_t > &a, GeographicLib::NearestNeighbor< dist_t, pos_t, distfun_t > &b)
Definition NearestNeighbor.hpp:819