PostGIS  2.2.7dev-r@@SVN_REVISION@@
double lwgeom_azumith_spheroid ( const LWPOINT r,
const LWPOINT s,
const SPHEROID spheroid 
)

Calculate the bearing between two points on a spheroid.

Calculate the bearing between two points on a spheroid.

Parameters
r- location of first point.
s- location of second point.
spheroid- spheroid definition.
Returns
azimuth - azimuth in radians.

Definition at line 2050 of file lwgeodetic.c.

References FP_EQUALS, geographic_point_init(), lwpoint_get_x(), lwpoint_get_y(), NAN, and spheroid_direction().

Referenced by geography_azimuth().

2051 {
2052  GEOGRAPHIC_POINT g1, g2;
2053  double x1, y1, x2, y2;
2054 
2055  /* Convert r to a geodetic point */
2056  x1 = lwpoint_get_x(r);
2057  y1 = lwpoint_get_y(r);
2058  geographic_point_init(x1, y1, &g1);
2059 
2060  /* Convert s to a geodetic point */
2061  x2 = lwpoint_get_x(s);
2062  y2 = lwpoint_get_y(s);
2063  geographic_point_init(x2, y2, &g2);
2064 
2065  /* Same point, return NaN */
2066  if ( FP_EQUALS(x1, x2) && FP_EQUALS(y1, y2) )
2067  {
2068  return NAN;
2069  }
2070 
2071  /* Do the direction calculation */
2072  return spheroid_direction(&g1, &g2, spheroid);
2073 }
double spheroid_direction(const GEOGRAPHIC_POINT *r, const GEOGRAPHIC_POINT *s, const SPHEROID *spheroid)
Computes the direction of the geodesic joining two points on the spheroid.
Definition: lwspheroid.c:268
#define NAN
Definition: lwgeodetic.h:22
Point in spherical coordinates on the world.
Definition: lwgeodetic.h:32
double lwpoint_get_x(const LWPOINT *point)
Definition: lwpoint.c:50
void geographic_point_init(double lon, double lat, GEOGRAPHIC_POINT *g)
Initialize a geographic point.
Definition: lwgeodetic.c:156
#define FP_EQUALS(A, B)
double lwpoint_get_y(const LWPOINT *point)
Definition: lwpoint.c:60

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