/Proj4/pj_qsfn.c

http://github.com/route-me/route-me · C · 19 lines · 16 code · 2 blank · 1 comment · 1 complexity · a9ad5a012919bbe464cc98ca01e7f796 MD5 · raw file 

    

  1. /* determine small q */
    2. 

  2. #ifndef lint
    3. 

  3. static const char SCCSID[]="@(#)pj_qsfn.c	4.3	93/06/12	GIE	REL";
    4. 

  4. #endif
    5. 

  5. #include <math.h>
    6. 

  6. #include "projects.h"
    7. 

  7. 

  8. # define EPSILON 1.0e-7
    9. 

  9. 	double
    10. 

  10. pj_qsfn(double sinphi, double e, double one_es) {
    11. 

  11. 	double con;
    12. 

  12. 

  13. 	if (e >= EPSILON) {
    14. 

  14. 		con = e * sinphi;
    15. 

  15. 		return (one_es * (sinphi / (1. - con * con) -
    16. 

  16. 		   (.5 / e) * log ((1. - con) / (1. + con))));
    17. 

  17. 	} else
    18. 

  18. 		return (sinphi + sinphi);
    19. 

  19. }
    20.