GeographicLib: AzimuthalEquidistant.hpp Source File

GeographicLib 2.7

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AzimuthalEquidistant.hpp
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1/**
2 * \file AzimuthalEquidistant.hpp
3 * \brief Header for GeographicLib::AzimuthalEquidistant class
4 *
5 * Copyright (c) Charles Karney (2009-2022) <karney@alum.mit.edu> and licensed
6 * under the MIT/X11 License. For more information, see
7 * https://geographiclib.sourceforge.io/
8 **********************************************************************/
9
10#if !defined(GEOGRAPHICLIB_AZIMUTHALEQUIDISTANT_HPP)
11#define GEOGRAPHICLIB_AZIMUTHALEQUIDISTANT_HPP 1
12
13#include <GeographicLib/Geodesic.hpp>
14#include <GeographicLib/Constants.hpp>
15
16namespace GeographicLib {
17
18 /**
19 * \brief Azimuthal equidistant projection
20 *
21 * Azimuthal equidistant projection centered at an arbitrary position on the
22 * ellipsoid. For a point in projected space (\e x, \e y), the geodesic
23 * distance from the center position is hypot(\e x, \e y) and the azimuth of
24 * the geodesic from the center point is atan2(\e x, \e y). The Forward and
25 * Reverse methods also return the azimuth \e azi of the geodesic at (\e x,
26 * \e y) and reciprocal scale \e rk in the azimuthal direction which,
27 * together with the basic properties of the projection, serve to specify
28 * completely the local affine transformation between geographic and
29 * projected coordinates.
30 *
31 * The conversions all take place using a Geodesic object (by default
32 * Geodesic::WGS84()). For more information on geodesics see \ref geodesic.
33 *
34 * Example of use:
35 * \include example-AzimuthalEquidistant.cpp
36 *
37 * <a href="GeodesicProj.1.html">GeodesicProj</a> is a command-line utility
38 * providing access to the functionality of AzimuthalEquidistant, Gnomonic,
39 * and CassiniSoldner.
40 **********************************************************************/
41
42 class GEOGRAPHICLIB_EXPORT AzimuthalEquidistant {
43 private:
44 typedef Math::real real;
45 real eps_;
46 Geodesic _earth;
47 public:
48
49 /**
50 * Constructor for AzimuthalEquidistant.
51 *
52 * @param[in] earth the Geodesic object to use for geodesic calculations.
53 * By default this uses the WGS84 ellipsoid.
54 **********************************************************************/
55 explicit AzimuthalEquidistant(const Geodesic& earth = Geodesic::WGS84());
56
57 /**
58 * Forward projection, from geographic to azimuthal equidistant.
59 *
60 * @param[in] lat0 latitude of center point of projection (degrees).
61 * @param[in] lon0 longitude of center point of projection (degrees).
62 * @param[in] lat latitude of point (degrees).
63 * @param[in] lon longitude of point (degrees).
64 * @param[out] x easting of point (meters).
65 * @param[out] y northing of point (meters).
66 * @param[out] azi azimuth of geodesic at point (degrees).
67 * @param[out] rk reciprocal of azimuthal scale at point.
68 *
69 * \e lat0 and \e lat should be in the range [&minus;90&deg;, 90&deg;].
70 * The scale of the projection is 1 in the "radial" direction, \e azi
71 * clockwise from true north, and is 1/\e rk in the direction perpendicular
72 * to this. A call to Forward followed by a call to Reverse will return
73 * the original (\e lat, \e lon) (to within roundoff).
74 **********************************************************************/
75 void Forward(real lat0, real lon0, real lat, real lon,
76 real& x, real& y, real& azi, real& rk) const;
77
78 /**
79 * Reverse projection, from azimuthal equidistant to geographic.
80 *
81 * @param[in] lat0 latitude of center point of projection (degrees).
82 * @param[in] lon0 longitude of center point of projection (degrees).
83 * @param[in] x easting of point (meters).
84 * @param[in] y northing of point (meters).
85 * @param[out] lat latitude of point (degrees).
86 * @param[out] lon longitude of point (degrees).
87 * @param[out] azi azimuth of geodesic at point (degrees).
88 * @param[out] rk reciprocal of azimuthal scale at point.
89 *
90 * \e lat0 should be in the range [&minus;90&deg;, 90&deg;]. \e lat will
91 * be in the range [&minus;90&deg;, 90&deg;] and \e lon will be in the
92 * range [&minus;180&deg;, 180&deg;]. The scale of the projection is 1 in
93 * the "radial" direction, \e azi clockwise from true north, and is 1/\e rk
94 * in the direction perpendicular to this. A call to Reverse followed by a
95 * call to Forward will return the original (\e x, \e y) (to roundoff) only
96 * if the geodesic to (\e x, \e y) is a shortest path.
97 **********************************************************************/
98 void Reverse(real lat0, real lon0, real x, real y,
99 real& lat, real& lon, real& azi, real& rk) const;
100
101 /**
102 * AzimuthalEquidistant::Forward without returning the azimuth and scale.
103 **********************************************************************/
104 void Forward(real lat0, real lon0, real lat, real lon,
105 real& x, real& y) const {
106 real azi, rk;
107 Forward(lat0, lon0, lat, lon, x, y, azi, rk);
108 }
109
110 /**
111 * AzimuthalEquidistant::Reverse without returning the azimuth and scale.
112 **********************************************************************/
113 void Reverse(real lat0, real lon0, real x, real y,
114 real& lat, real& lon) const {
115 real azi, rk;
116 Reverse(lat0, lon0, x, y, lat, lon, azi, rk);
117 }
118
119 /** \name Inspector functions
120 **********************************************************************/
121 ///@{
122 /**
123 * @return \e a the equatorial radius of the ellipsoid (meters). This is
124 * the value inherited from the Geodesic object used in the constructor.
125 **********************************************************************/
126 Math::real EquatorialRadius() const { return _earth.EquatorialRadius(); }
127
128 /**
129 * @return \e f the flattening of the ellipsoid. This is the value
130 * inherited from the Geodesic object used in the constructor.
131 **********************************************************************/
132 Math::real Flattening() const { return _earth.Flattening(); }
133 ///@}
134
135 };
136
137} // namespace GeographicLib
138
139#endif // GEOGRAPHICLIB_AZIMUTHALEQUIDISTANT_HPP
Constants.hpp
Header for GeographicLib::Constants class.
GEOGRAPHICLIB_EXPORT
#define GEOGRAPHICLIB_EXPORT
Definition Constants.hpp:59
Geodesic.hpp
Header for GeographicLib::Geodesic class.
GeographicLib::AzimuthalEquidistant::Flattening
Math::real Flattening() const
Definition AzimuthalEquidistant.hpp:132
GeographicLib::AzimuthalEquidistant::EquatorialRadius
Math::real EquatorialRadius() const
Definition AzimuthalEquidistant.hpp:126
GeographicLib::AzimuthalEquidistant::Forward
void Forward(real lat0, real lon0, real lat, real lon, real &x, real &y) const
Definition AzimuthalEquidistant.hpp:104
GeographicLib::AzimuthalEquidistant::AzimuthalEquidistant
AzimuthalEquidistant(const Geodesic &earth=Geodesic::WGS84())
Definition AzimuthalEquidistant.cpp:16
GeographicLib::AzimuthalEquidistant::Reverse
void Reverse(real lat0, real lon0, real x, real y, real &lat, real &lon) const
Definition AzimuthalEquidistant.hpp:113
GeographicLib::AzimuthalEquidistant::Forward
void Forward(real lat0, real lon0, real lat, real lon, real &x, real &y, real &azi, real &rk) const
Definition AzimuthalEquidistant.cpp:20
GeographicLib::AzimuthalEquidistant::Reverse
void Reverse(real lat0, real lon0, real x, real y, real &lat, real &lon, real &azi, real &rk) const
Definition AzimuthalEquidistant.cpp:30
GeographicLib::Geodesic
Geodesic calculations
Definition Geodesic.hpp:175
GeographicLib::Geodesic::WGS84
static const Geodesic & WGS84()
Definition Geodesic.cpp:94
GeographicLib::Math::real
double real
Definition Math.hpp:115
GeographicLib
Namespace for GeographicLib.
Definition Accumulator.cpp:12