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SpherePoint.h
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1/*
2 * Developed for the LSST Data Management System.
3 * This product includes software developed by the LSST Project
4 * (https://www.lsst.org).
5 * See the COPYRIGHT file at the top-level directory of this distribution
6 * for details of code ownership.
7 *
8 * This program is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see <https://www.gnu.org/licenses/>.
20 */
21
22#ifndef LSST_GEOM_SPHEREPOINT_H_
23#define LSST_GEOM_SPHEREPOINT_H_
24
25#include <cmath>
26#include <ostream>
27#include <utility>
28
31#include "lsst/geom/Angle.h"
32#include "lsst/geom/Point.h"
33
34namespace lsst {
35namespace geom {
36
57class SpherePoint final {
58public:
72 SpherePoint(Angle const& longitude, Angle const& latitude);
73
88 SpherePoint(double longitude, double latitude, AngleUnit units);
89
105 explicit SpherePoint(sphgeom::Vector3d const& vector);
106
114 SpherePoint(sphgeom::LonLat const& lonLat) noexcept;
115
117 SpherePoint() noexcept;
118
126 SpherePoint(SpherePoint const& other) noexcept;
127
134 SpherePoint(SpherePoint&& other) noexcept;
135
136 ~SpherePoint() noexcept;
137
150 SpherePoint& operator=(SpherePoint const& other) noexcept;
151
158 SpherePoint& operator=(SpherePoint&& other) noexcept;
159
165 operator sphgeom::LonLat() const noexcept;
166
167 /*
168 * Accessors
169 */
170
178 Angle getLongitude() const noexcept { return _longitude * radians; };
179
181 Angle getRa() const noexcept { return _longitude * radians; };
182
190 Angle getLatitude() const noexcept { return _latitude * radians; };
191
193 Angle getDec() const noexcept { return _latitude * radians; };
194
202 Point2D getPosition(AngleUnit unit) const noexcept;
203
211 sphgeom::UnitVector3d getVector() const noexcept;
212
227 Angle operator[](size_t index) const;
228
237 bool atPole() const noexcept {
238 // Unit tests indicate we don't need to worry about epsilon-errors, in that
239 // Objects constructed from lat=90*degrees, <0,0,1>, etc. all have atPole() = true.
240 return fabs(_latitude) >= HALFPI;
241 }
242
252 bool isFinite() const noexcept;
253
254 /*
255 * Comparisons between points
256 */
257
278 bool operator==(SpherePoint const& other) const noexcept;
279
286 bool operator!=(SpherePoint const& other) const noexcept;
287
289 std::size_t hash_value() const noexcept;
290
310 Angle bearingTo(SpherePoint const& other) const;
311
321 Angle separation(SpherePoint const& other) const noexcept;
322
323 /*
324 * Transformations of points
325 */
326
338 SpherePoint rotated(SpherePoint const& axis, Angle const& amount) const noexcept;
339
356 SpherePoint offset(Angle const& bearing, Angle const& amount) const;
357
366 std::pair<Angle, Angle> getTangentPlaneOffset(SpherePoint const& other) const;
367
368private:
369 double _longitude; // radians
370 double _latitude; // radians
371
373 void _set(sphgeom::UnitVector3d const& unitVector);
374};
375
383SpherePoint averageSpherePoint(std::vector<SpherePoint> const& coords);
384
385/*
386 * Object-level display
387 */
388
409std::ostream& operator<<(std::ostream& os, SpherePoint const& point);
410
411} // namespace geom
412} // namespace lsst
413
414namespace std {
415template <>
419 size_t operator()(argument_type const& x) const noexcept { return x.hash_value(); }
420};
421} // namespace std
422
423#endif /* LSST_GEOM_SPHEREPOINT_H_ */
This file declares a class for representing unit vectors in ℝ³.
This file declares a class for representing vectors in ℝ³.
A class representing an angle.
Definition Angle.h:128
A class used to convert scalar POD types such as double to Angle.
Definition Angle.h:71
Point in an unspecified spherical coordinate system.
Definition SpherePoint.h:57
std::pair< Angle, Angle > getTangentPlaneOffset(SpherePoint const &other) const
Get the offset from a tangent plane centered at this point to another point.
SpherePoint offset(Angle const &bearing, Angle const &amount) const
Return a point offset from this one along a great circle.
SpherePoint(SpherePoint const &other) noexcept
Create a copy of a SpherePoint.
bool isFinite() const noexcept
true if this point is a well-defined position.
operator sphgeom::LonLat() const noexcept
Make SpherePoint implicitly convertible to LonLat.
Point2D getPosition(AngleUnit unit) const noexcept
Return longitude, latitude as a Point2D object.
Angle bearingTo(SpherePoint const &other) const
Orientation at this point of the great circle arc to another point.
bool atPole() const noexcept
true if this point is either coordinate pole.
SpherePoint(Angle const &longitude, Angle const &latitude)
Construct a SpherePoint from a longitude and latitude.
Angle separation(SpherePoint const &other) const noexcept
Angular distance between two points.
SpherePoint(SpherePoint &&other) noexcept
Create a copy of a SpherePoint.
sphgeom::UnitVector3d getVector() const noexcept
A unit vector representation of this point.
SpherePoint() noexcept
Construct a SpherePoint with "nan" for longitude and latitude.
Angle getLatitude() const noexcept
The latitude of this point.
Angle getLongitude() const noexcept
The longitude of this point.
SpherePoint rotated(SpherePoint const &axis, Angle const &amount) const noexcept
Return a point rotated from this one around an axis.
Angle getDec() const noexcept
Synonym for getLatitude.
Angle getRa() const noexcept
Synonym for getLongitude.
LonLat represents a spherical coordinate (longitude/latitude angle) pair.
Definition LonLat.h:55
UnitVector3d is a unit vector in ℝ³ with components stored in double precision.
Vector3d is a vector in ℝ³ with components stored in double precision.
Definition Vector3d.h:51
double constexpr HALFPI
Definition Angle.h:42
std::size_t hash_value(Extent< T, N > const &extent) noexcept
Definition Extent.cc:127
SpherePoint averageSpherePoint(std::vector< SpherePoint > const &coords)
Return the average of a list of coordinates.
AngleUnit constexpr radians
constant with units of radians
Definition Angle.h:109
Point< double, 2 > Point2D
Definition Point.h:324
STL namespace.
lsst::geom::SpherePoint argument_type
size_t operator()(argument_type const &x) const noexcept