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/Proj4/PJ_fouc_s.c

http://github.com/route-me/route-me
C | 48 lines | 46 code | 2 blank | 0 comment | 7 complexity | c30ebab0f1da09140f96f3685b57ddec MD5 | raw file
    

  1. #ifndef lint
    2. 

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

  3. #endif
    4. 

  4. #define PROJ_PARMS__ \
    5. 

  5. 	double n, n1;
    6. 

  6. #define PJ_LIB__
    7. 

  7. #include	"projects.h"
    8. 

  8. PROJ_HEAD(fouc_s, "Foucaut Sinusoidal") "\n\tPCyl., Sph.";
    9. 

  9. #define MAX_ITER    10
    10. 

  10. #define LOOP_TOL    1e-7
    11. 

  11. FORWARD(s_forward); /* spheroid */
    12. 

  12. 	double t;
    13. 

  13. 

  14. 	t = cos(lp.phi);
    15. 

  15. 	xy.x = lp.lam * t / (P->n + P->n1 * t);
    16. 

  16. 	xy.y = P->n * lp.phi + P->n1 * sin(lp.phi);
    17. 

  17. 	return (xy);
    18. 

  18. }
    19. 

  19. INVERSE(s_inverse); /* spheroid */
    20. 

  20. 	double V;
    21. 

  21. 	int i;
    22. 

  22. 

  23. 	if (P->n) {
    24. 

  24. 		lp.phi = xy.y;
    25. 

  25. 		for (i = MAX_ITER; i ; --i) {
    26. 

  26. 			lp.phi -= V = (P->n * lp.phi + P->n1 * sin(lp.phi) - xy.y ) /
    27. 

  27. 				(P->n + P->n1 * cos(lp.phi));
    28. 

  28. 			if (fabs(V) < LOOP_TOL)
    29. 

  29. 				break;
    30. 

  30. 		}
    31. 

  31. 		if (!i)
    32. 

  32. 			lp.phi = xy.y < 0. ? -HALFPI : HALFPI;
    33. 

  33. 	} else
    34. 

  34. 		lp.phi = aasin(xy.y);
    35. 

  35. 	V = cos(lp.phi);
    36. 

  36. 	lp.lam = xy.x * (P->n + P->n1 * V) / V;
    37. 

  37. 	return (lp);
    38. 

  38. }
    39. 

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

  40. ENTRY0(fouc_s)
    41. 

  41. 	P->n = pj_param(P->params, "dn").f;
    42. 

  42. 	if (P->n < 0. || P->n > 1.)
    43. 

  43. 		E_ERROR(-99)
    44. 

  44. 	P->n1 = 1. - P->n;
    45. 

  45. 	P->es = 0;
    46. 

  46. 	P->inv = s_inverse;
    47. 

  47. 	P->fwd = s_forward;
    48. 

  48. ENDENTRY(P)
    49. 

  49.