/Proj4/PJ_nocol.c

http://github.com/route-me/route-me · C · 41 lines · 40 code · 1 blank · 0 comment · 9 complexity · 3321af5bf85b7e40f34c9d032191de46 MD5 · raw file 

    

  1. #ifndef lint
    2. 

  2. static const char SCCSID[]="@(#)PJ_nocol.c	4.1	94/02/15	GIE	REL";
    3. 

  3. #endif
    4. 

  4. #define PJ_LIB__
    5. 

  5. #include	"projects.h"
    6. 

  6. PROJ_HEAD(nicol, "Nicolosi Globular") "\n\tMisc Sph, no inv.";
    7. 

  7. #define EPS	1e-10
    8. 

  8. FORWARD(s_forward); /* spheroid */
    9. 

  9. 	if (fabs(lp.lam) < EPS) {
    10. 

  10. 		xy.x = 0;
    11. 

  11. 		xy.y = lp.phi;
    12. 

  12. 	} else if (fabs(lp.phi) < EPS) {
    13. 

  13. 		xy.x = lp.lam;
    14. 

  14. 		xy.y = 0.;
    15. 

  15. 	} else if (fabs(fabs(lp.lam) - HALFPI) < EPS) {
    16. 

  16. 		xy.x = lp.lam * cos(lp.phi);
    17. 

  17. 		xy.y = HALFPI * sin(lp.phi);
    18. 

  18. 	} else if (fabs(fabs(lp.phi) - HALFPI) < EPS) {
    19. 

  19. 		xy.x = 0;
    20. 

  20. 		xy.y = lp.phi;
    21. 

  21. 	} else {
    22. 

  22. 		double tb, c, d, m, n, r2, sp;
    23. 

  23. 

  24. 		tb = HALFPI / lp.lam - lp.lam / HALFPI;
    25. 

  25. 		c = lp.phi / HALFPI;
    26. 

  26. 		d = (1 - c * c)/((sp = sin(lp.phi)) - c);
    27. 

  27. 		r2 = tb / d;
    28. 

  28. 		r2 *= r2;
    29. 

  29. 		m = (tb * sp / d - 0.5 * tb)/(1. + r2);
    30. 

  30. 		n = (sp / r2 + 0.5 * d)/(1. + 1./r2);
    31. 

  31. 		xy.x = cos(lp.phi);
    32. 

  32. 		xy.x = sqrt(m * m + xy.x * xy.x / (1. + r2));
    33. 

  33. 		xy.x = HALFPI * ( m + (lp.lam < 0. ? -xy.x : xy.x));
    34. 

  34. 		xy.y = sqrt(n * n - (sp * sp / r2 + d * sp - 1.) /
    35. 

  35. 			(1. + 1./r2));
    36. 

  36. 		xy.y = HALFPI * ( n + (lp.phi < 0. ? xy.y : -xy.y ));
    37. 

  37. 	}
    38. 

  38. 	return (xy);
    39. 

  39. }
    40. 

  40. FREEUP; if (P) pj_dalloc(P); }
    41. 

  41. ENTRY0(nicol) P->es = 0.; P->fwd = s_forward; ENDENTRY(P)
    42.