/Proj4/pj_qsfn.c
C | 19 lines | 16 code | 2 blank | 1 comment | 1 complexity | a9ad5a012919bbe464cc98ca01e7f796 MD5 | raw file
1/* determine small q */ 2#ifndef lint 3static const char SCCSID[]="@(#)pj_qsfn.c 4.3 93/06/12 GIE REL"; 4#endif 5#include <math.h> 6#include "projects.h" 7 8# define EPSILON 1.0e-7 9 double 10pj_qsfn(double sinphi, double e, double one_es) { 11 double con; 12 13 if (e >= EPSILON) { 14 con = e * sinphi; 15 return (one_es * (sinphi / (1. - con * con) - 16 (.5 / e) * log ((1. - con) / (1. + con)))); 17 } else 18 return (sinphi + sinphi); 19}