PostGIS  2.2.8dev-r@@SVN_REVISION@@

## ◆ vector_angle()

 double vector_angle ( const POINT3D * v1, const POINT3D * v2 )

Angle between two unit vectors.

Definition at line 455 of file lwgeodetic.c.

References cross_product(), dot_product(), normalize(), pixval::x, and pixval::y.

Referenced by test_vector_angle().

456 {
457  POINT3D v3, normal;
458  double angle, x, y;
459
460  cross_product(v1, v2, &normal);
461  normalize(&normal);
462  cross_product(&normal, v1, &v3);
463
464  x = dot_product(v1, v2);
465  y = dot_product(v2, &v3);
466
467  angle = atan2(y, x);
468  return angle;
469 }
void normalize(POINT3D *p)
Normalize to a unit vector.
Definition: lwgeodetic.c:565
static double dot_product(const POINT3D *p1, const POINT3D *p2)
Convert cartesion coordinates on unit sphere to lon/lat coordinates static void cart2ll(const POINT3D...
Definition: lwgeodetic.c:396
static void cross_product(const POINT3D *a, const POINT3D *b, POINT3D *n)
Calculate the cross product of two vectors.
Definition: lwgeodetic.c:404
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