MySQL  8.0.28
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longitude_range_normalizer.h
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1 #ifndef SQL_GIS_LONGITUDE_RANGE_NORMALIZER_H_INCLUDED
2 #define SQL_GIS_LONGITUDE_RANGE_NORMALIZER_H_INCLUDED
3 
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25 
26 /// @file
27 ///
28 /// Implements a longitude normalizer that converts longitude coordinates
29 /// outside the range such that geometries wrap correctly across
30 /// the 180/-180 boundary on the globe.
31 
32 #include <cmath> // M_PI
33 
34 #include "sql/dd/types/spatial_reference_system.h" // dd::Spatial_reference_system
36 
37 namespace gis {
38 
40  private:
42 
43  public:
44  /// Construct a new longitude range normalizer.
45  ///
46  /// @param srs The spatial reference system of the geometry.
48  : m_srs(srs) {}
49 
50  using Nop_visitor::visit;
51  bool visit(Point *pt) override {
52  double lon = pt->x() - m_srs->prime_meridian() * m_srs->angular_unit();
53  if (!m_srs->positive_east()) lon *= -1.0;
54  if (lon <= -M_PI) {
55  // Longitude -180 or less, so we add 360 (2*pi): e.g. -182 + 360 = 178
56  pt->x(lon + 2.0 * M_PI);
57  } else if (lon > M_PI) {
58  // Longitude over 180, so we subtract 360 (2*pi): e.g. 181 - 360 = -179
59  pt->x(lon - 2.0 * M_PI);
60  }
61  return false;
62  }
63 };
64 
65 } // namespace gis
66 
67 #endif // SQL_GIS_LONGITUDE_RANGE_NORMALIZER_H_INCLUDED
Definition: spatial_reference_system.h:52
virtual double angular_unit() const =0
virtual bool positive_east() const =0
virtual double prime_meridian() const =0
Definition: longitude_range_normalizer.h:39
Longitude_range_normalizer(const dd::Spatial_reference_system *srs)
Construct a new longitude range normalizer.
Definition: longitude_range_normalizer.h:47
const dd::Spatial_reference_system * m_srs
Definition: longitude_range_normalizer.h:41
bool visit(Point *pt) override
Definition: longitude_range_normalizer.h:51
A visitor that implements the entire interface and does nothing.
Definition: geometry_visitor.h:121
bool visit(Geometry *) override
Visits a geometry.
Definition: geometry_visitor.h:158
A 2d point.
Definition: geometries.h:149
double x() const
Gets the first coordinate value.
Definition: geometries.cc:45
The geometries implement a hierarchical visitor pattern.
Definition: area.cc:46