/Proj4/PJ_putp6.c

http://github.com/route-me/route-me · C · 62 lines · 60 code · 2 blank · 0 comment · 4 complexity · 97fa2093a30a8aaf02d04453ecf707cf MD5 · raw file 

    

  1. #ifndef lint
    2. 

  2. static const char SCCSID[]="@(#)PJ_putp6.c	4.1	94/02/15	GIE	REL";
    3. 

  3. #endif
    4. 

  4. #define PROJ_PARMS__ \
    5. 

  5. 	double C_x, C_y, A, B, D;
    6. 

  6. #define PJ_LIB__
    7. 

  7. #include	"projects.h"
    8. 

  8. PROJ_HEAD(putp6, "Putnins P6") "\n\tPCyl., Sph.";
    9. 

  9. PROJ_HEAD(putp6p, "Putnins P6'") "\n\tPCyl., Sph.";
    10. 

  10. #define EPS	1e-10
    11. 

  11. #define NITER	10
    12. 

  12. #define CON_POLE 1.732050807568877
    13. 

  13. FORWARD(s_forward); /* spheroid */
    14. 

  14. 	double p, r, V;
    15. 

  15. 	int i;
    16. 

  16. 

  17. 	p = P->B * sin(lp.phi);
    18. 

  18. 	lp.phi *=  1.10265779;
    19. 

  19. 	for (i = NITER; i ; --i) {
    20. 

  20. 		r = sqrt(1. + lp.phi * lp.phi);
    21. 

  21. 		lp.phi -= V = ( (P->A - r) * lp.phi - log(lp.phi + r) - p ) /
    22. 

  22. 			(P->A - 2. * r);
    23. 

  23. 		if (fabs(V) < EPS)
    24. 

  24. 			break;
    25. 

  25. 	}
    26. 

  26. 	if (!i)
    27. 

  27. 		lp.phi = p < 0. ? -CON_POLE : CON_POLE;
    28. 

  28. 	xy.x = P->C_x * lp.lam * (P->D - sqrt(1. + lp.phi * lp.phi));
    29. 

  29. 	xy.y = P->C_y * lp.phi;
    30. 

  30. 	return (xy);
    31. 

  31. }
    32. 

  32. INVERSE(s_inverse); /* spheroid */
    33. 

  33. 	double r;
    34. 

  34. 

  35. 	lp.phi = xy.y / P->C_y;
    36. 

  36. 	r = sqrt(1. + lp.phi * lp.phi);
    37. 

  37. 	lp.lam = xy.x / (P->C_x * (P->D - r));
    38. 

  38. 	lp.phi = aasin( ( (P->A - r) * lp.phi - log(lp.phi + r) ) / P->B);
    39. 

  39. 	return (lp);
    40. 

  40. }
    41. 

  41. FREEUP; if (P) pj_dalloc(P); }
    42. 

  42. 	static PJ *
    43. 

  43. setup(PJ *P) {
    44. 

  44. 	P->es = 0.;
    45. 

  45. 	P->inv = s_inverse;
    46. 

  46. 	P->fwd = s_forward;
    47. 

  47. 	return P;
    48. 

  48. }
    49. 

  49. ENTRY0(putp6)
    50. 

  50. 	P->C_x = 1.01346;
    51. 

  51. 	P->C_y = 0.91910;
    52. 

  52. 	P->A   = 4.;
    53. 

  53. 	P->B   = 2.1471437182129378784;
    54. 

  54. 	P->D   = 2.;
    55. 

  55. ENDENTRY(setup(P))
    56. 

  56. ENTRY0(putp6p)
    57. 

  57. 	P->C_x = 0.44329;
    58. 

  58. 	P->C_y = 0.80404;
    59. 

  59. 	P->A   = 6.;
    60. 

  60. 	P->B   = 5.61125;
    61. 

  61. 	P->D   = 3.;
    62. 

  62. ENDENTRY(setup(P))
    63.