LSSTApplications  18.1.0
LSSTDataManagementBasePackage
LonLat.cc
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2  * LSST Data Management System
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22 
25 
26 #include "lsst/sphgeom/LonLat.h"
27 
28 #include <cmath>
29 #include <ostream>
30 
31 #include "lsst/sphgeom/Vector3d.h"
32 
33 
34 namespace lsst {
35 namespace sphgeom {
36 
38  double d2 = v(0) * v(0) + v(1) * v(1);
39  double lat = 0.0;
40  if (v(2) != 0.0) {
41  lat = std::atan2(v(2), sqrt(d2));
42  if (std::fabs(lat) > 0.5 * PI) {
43  lat = ::copysign(0.5 * PI, lat);
44  }
45  }
46  return Angle(lat);
47 }
48 
50  double d2 = v(0) * v(0) + v(1) * v(1);
51  double lon = 0.0;
52  if (d2 != 0.0) {
53  lon = std::atan2(v(1), v(0));
54  if (lon < 0.0) {
55  lon += 2*PI;
56  }
57  }
58  return NormalizedAngle(lon);
59 }
60 
61 
62 LonLat::LonLat(NormalizedAngle lon, Angle lat) : _lon(lon), _lat(lat) {
63  if (std::fabs(_lat.asRadians()) > 0.5 * PI) {
64  throw std::invalid_argument("invalid latitude angle");
65  }
66  _enforceInvariants();
67 }
68 
69 LonLat::LonLat(Vector3d const & v) : _lon(longitudeOf(v)), _lat(latitudeOf(v)) {
70  _enforceInvariants();
71 }
72 
73 void LonLat::_enforceInvariants() {
74  // Make sure that if one coordinate is NaN, the other is as well.
75  if (_lon.isNan()) {
76  _lat = Angle::nan();
77  } else if (_lat.isNan()) {
78  _lon = NormalizedAngle::nan();
79  }
80 }
81 
83  return os << '[' << p.getLon() << ", " << p.getLat() << ']';
84 }
85 
86 }} // namespace lsst::sphgeom
NormalizedAngle is an angle that lies in the range [0, 2π), with one exception - a NormalizedAngle ca...
bool isNan() const
isNan returns true if the angle value is NaN.
Definition: Angle.h:91
Angle getLat() const
Definition: LonLat.h:90
std::ostream & operator<<(std::ostream &, Angle const &)
Definition: Angle.cc:34
Vector3d is a vector in ℝ³ with components stored in double precision.
Definition: Vector3d.h:44
static NormalizedAngle longitudeOf(Vector3d const &v)
longitudeOf returns the longitude of the point on the unit sphere corresponding to the direction of v...
Definition: LonLat.cc:49
NormalizedAngle getLon() const
Definition: LonLat.h:88
T atan2(T... args)
This file declares a class for representing vectors in ℝ³.
bool isNan() const
isNan returns true if the angle value is NaN.
A base class for image defects.
double asRadians() const
asRadians returns the value of this angle in units of radians.
Definition: Angle.h:85
constexpr double PI
Definition: constants.h:36
static Angle latitudeOf(Vector3d const &v)
latitudeOf returns the latitude of the point on the unit sphere corresponding to the direction of v...
Definition: LonLat.cc:37
static NormalizedAngle nan()
T fabs(T... args)
static Angle nan()
Definition: Angle.h:45
Angle represents an angle in radians.
Definition: Angle.h:43
LonLat represents a spherical coordinate (longitude/latitude angle) pair.
Definition: LonLat.h:48
LonLat()
This constructor creates the point with longitude and latitude angle equal to zero.
Definition: LonLat.h:70
lsst::geom::Angle Angle
Definition: misc.h:33
STL class.
This file contains a class representing spherical coordinates.
std::ostream * os
Definition: Schema.cc:746