/usr/include/GeographicLib/TransverseMercator.hpp is in libgeographic-dev 1.45-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | /**
* \file TransverseMercator.hpp
* \brief Header for GeographicLib::TransverseMercator class
*
* Copyright (c) Charles Karney (2008-2015) <charles@karney.com> and licensed
* under the MIT/X11 License. For more information, see
* http://geographiclib.sourceforge.net/
**********************************************************************/
#if !defined(GEOGRAPHICLIB_TRANSVERSEMERCATOR_HPP)
#define GEOGRAPHICLIB_TRANSVERSEMERCATOR_HPP 1
#include <GeographicLib/Constants.hpp>
#if !defined(GEOGRAPHICLIB_TRANSVERSEMERCATOR_ORDER)
/**
* The order of the series approximation used in TransverseMercator.
* GEOGRAPHICLIB_TRANSVERSEMERCATOR_ORDER can be set to any integer in [4, 8].
**********************************************************************/
# define GEOGRAPHICLIB_TRANSVERSEMERCATOR_ORDER \
(GEOGRAPHICLIB_PRECISION == 2 ? 6 : \
(GEOGRAPHICLIB_PRECISION == 1 ? 4 : 8))
#endif
namespace GeographicLib {
/**
* \brief Transverse Mercator projection
*
* This uses Krüger's method which evaluates the projection and its
* inverse in terms of a series. See
* - L. Krüger,
* <a href="https://dx.doi.org/10.2312/GFZ.b103-krueger28"> Konforme
* Abbildung des Erdellipsoids in der Ebene</a> (Conformal mapping of the
* ellipsoidal earth to the plane), Royal Prussian Geodetic Institute, New
* Series 52, 172 pp. (1912).
* - C. F. F. Karney,
* <a href="https://dx.doi.org/10.1007/s00190-011-0445-3">
* Transverse Mercator with an accuracy of a few nanometers,</a>
* J. Geodesy 85(8), 475--485 (Aug. 2011);
* preprint
* <a href="http://arxiv.org/abs/1002.1417">arXiv:1002.1417</a>.
*
* Krüger's method has been extended from 4th to 6th order. The maximum
* error is 5 nm (5 nanometers), ground distance, for all positions within 35
* degrees of the central meridian. The error in the convergence is 2
* × 10<sup>−15</sup>" and the relative error in the scale
* is 6 × 10<sup>−12</sup>%%. See Sec. 4 of
* <a href="http://arxiv.org/abs/1002.1417">arXiv:1002.1417</a> for details.
* The speed penalty in going to 6th order is only about 1%.
*
* There's a singularity in the projection at φ = 0°, λ
* − λ<sub>0</sub> = ±(1 − \e e)90° (≈
* ±82.6° for the WGS84 ellipsoid), where \e e is the
* eccentricity. Beyond this point, the series ceases to converge and the
* results from this method will be garbage. To be on the safe side, don't
* use this method if the angular distance from the central meridian exceeds
* (1 − 2e)90° (≈ 75° for the WGS84 ellipsoid)
*
* TransverseMercatorExact is an alternative implementation of the projection
* using exact formulas which yield accurate (to 8 nm) results over the
* entire ellipsoid.
*
* The ellipsoid parameters and the central scale are set in the constructor.
* The central meridian (which is a trivial shift of the longitude) is
* specified as the \e lon0 argument of the TransverseMercator::Forward and
* TransverseMercator::Reverse functions. The latitude of origin is taken to
* be the equator. There is no provision in this class for specifying a
* false easting or false northing or a different latitude of origin.
* However these are can be simply included by the calling function. For
* example, the UTMUPS class applies the false easting and false northing for
* the UTM projections. A more complicated example is the British National
* Grid (<a href="http://www.spatialreference.org/ref/epsg/7405/">
* EPSG:7405</a>) which requires the use of a latitude of origin. This is
* implemented by the GeographicLib::OSGB class.
*
* See TransverseMercator.cpp for more information on the implementation.
*
* See \ref transversemercator for a discussion of this projection.
*
* Example of use:
* \include example-TransverseMercator.cpp
*
* <a href="TransverseMercatorProj.1.html">TransverseMercatorProj</a> is a
* command-line utility providing access to the functionality of
* TransverseMercator and TransverseMercatorExact.
**********************************************************************/
class GEOGRAPHICLIB_EXPORT TransverseMercator {
private:
typedef Math::real real;
static const int maxpow_ = GEOGRAPHICLIB_TRANSVERSEMERCATOR_ORDER;
static const int numit_ = 5;
real _a, _f, _k0, _e2, _es, _e2m, _c, _n;
// _alp[0] and _bet[0] unused
real _a1, _b1, _alp[maxpow_ + 1], _bet[maxpow_ + 1];
friend class Ellipsoid; // For access to taupf, tauf.
public:
/**
* 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.
* @param[in] k0 central scale factor.
* @exception GeographicErr if \e a, (1 − \e f) \e a, or \e k0 is
* not positive.
**********************************************************************/
TransverseMercator(real a, real f, real k0);
/**
* Forward projection, from geographic to transverse Mercator.
*
* @param[in] lon0 central meridian of the projection (degrees).
* @param[in] lat latitude of point (degrees).
* @param[in] lon longitude of point (degrees).
* @param[out] x easting of point (meters).
* @param[out] y northing of point (meters).
* @param[out] gamma meridian convergence at point (degrees).
* @param[out] k scale of projection at point.
*
* No false easting or northing is added. \e lat should be in the range
* [−90°, 90°].
**********************************************************************/
void Forward(real lon0, real lat, real lon,
real& x, real& y, real& gamma, real& k) const;
/**
* Reverse projection, from transverse Mercator to geographic.
*
* @param[in] lon0 central meridian of the projection (degrees).
* @param[in] x easting of point (meters).
* @param[in] y northing of point (meters).
* @param[out] lat latitude of point (degrees).
* @param[out] lon longitude of point (degrees).
* @param[out] gamma meridian convergence at point (degrees).
* @param[out] k scale of projection at point.
*
* No false easting or northing is added. The value of \e lon returned is
* in the range [−180°, 180°).
**********************************************************************/
void Reverse(real lon0, real x, real y,
real& lat, real& lon, real& gamma, real& k) const;
/**
* TransverseMercator::Forward without returning the convergence and scale.
**********************************************************************/
void Forward(real lon0, real lat, real lon,
real& x, real& y) const {
real gamma, k;
Forward(lon0, lat, lon, x, y, gamma, k);
}
/**
* TransverseMercator::Reverse without returning the convergence and scale.
**********************************************************************/
void Reverse(real lon0, real x, real y,
real& lat, real& lon) const {
real gamma, k;
Reverse(lon0, x, y, lat, lon, gamma, k);
}
/** \name Inspector functions
**********************************************************************/
///@{
/**
* @return \e a the equatorial radius of the ellipsoid (meters). This is
* the value used in the constructor.
**********************************************************************/
Math::real MajorRadius() const { return _a; }
/**
* @return \e f the flattening of the ellipsoid. This is the value used in
* the constructor.
**********************************************************************/
Math::real Flattening() const { return _f; }
/// \cond SKIP
/**
* <b>DEPRECATED</b>
* @return \e r the inverse flattening of the ellipsoid.
**********************************************************************/
Math::real InverseFlattening() const { return 1/_f; }
/// \endcond
/**
* @return \e k0 central scale for the projection. This is the value of \e
* k0 used in the constructor and is the scale on the central meridian.
**********************************************************************/
Math::real CentralScale() const { return _k0; }
///@}
/**
* A global instantiation of TransverseMercator with the WGS84 ellipsoid
* and the UTM scale factor. However, unlike UTM, no false easting or
* northing is added.
**********************************************************************/
static const TransverseMercator& UTM();
};
} // namespace GeographicLib
#endif // GEOGRAPHICLIB_TRANSVERSEMERCATOR_HPP
|