PostGIS  2.2.8dev-r@@SVN_REVISION@@

◆ deltaLongitude()

double deltaLongitude ( double  azimuth,
double  sigma,
double  tsm,
SPHEROID sphere 
)

Definition at line 130 of file lwgeom_spheroid.c.

References SPHEROID::f.

Referenced by distance_ellipse_calculation(), and spheroid_parallel_arc_length().

131 {
132  /* compute the expansion C */
133  double das,C;
134  double ctsm,DL;
135 
136  das = cos(azimuth)*cos(azimuth);
137  C = sphere->f/16.0 * das * (4.0 + sphere->f * (4.0 - 3.0 * das));
138 
139  /* compute the difference in longitude */
140  ctsm = cos(tsm);
141  DL = ctsm + C * cos(sigma) * (-1.0 + 2.0 * ctsm*ctsm);
142  DL = sigma + C * sin(sigma) * DL;
143  return (1.0 - C) * sphere->f * sin(azimuth) * DL;
144 }
double f
Definition: liblwgeom.h:299
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