/Proj4/PJ_ocea.c

http://github.com/route-me/route-me · C · 71 lines · 65 code · 3 blank · 3 comment · 4 complexity · 9845d1090fd8992c0d2fa94d056c08dc MD5 · raw file 

    

  1. #ifndef lint
    2. 

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

  3. #endif
    4. 

  4. #define PROJ_PARMS__ \
    5. 

  5. 	double	rok; \
    6. 

  6. 	double	rtk; \
    7. 

  7. 	double	sinphi; \
    8. 

  8. 	double	cosphi; \
    9. 

  9. 	double	singam; \
    10. 

  10. 	double	cosgam;
    11. 

  11. #define PJ_LIB__
    12. 

  12. #include	"projects.h"
    13. 

  13. PROJ_HEAD(ocea, "Oblique Cylindrical Equal Area") "\n\tCyl, Sph"
    14. 

  14. 	"lonc= alpha= or\n\tlat_1= lat_2= lon_1= lon_2=";
    15. 

  15. FORWARD(s_forward); /* spheroid */
    16. 

  16. 	double t;
    17. 

  17. 

  18. 	xy.y = sin(lp.lam);
    19. 

  19. /*
    20. 

  20. 	xy.x = atan2((tan(lp.phi) * P->cosphi + P->sinphi * xy.y) , cos(lp.lam));
    21. 

  21. */
    22. 

  22. 	t = cos(lp.lam);
    23. 

  23. 	xy.x = atan((tan(lp.phi) * P->cosphi + P->sinphi * xy.y) / t);
    24. 

  24. 	if (t < 0.)
    25. 

  25. 		xy.x += PI;
    26. 

  26. 	xy.x *= P->rtk;
    27. 

  27. 	xy.y = P->rok * (P->sinphi * sin(lp.phi) - P->cosphi * cos(lp.phi) * xy.y);
    28. 

  28. 	return (xy);
    29. 

  29. }
    30. 

  30. INVERSE(s_inverse); /* spheroid */
    31. 

  31. 	double t, s;
    32. 

  32. 

  33. 	xy.y /= P->rok;
    34. 

  34. 	xy.x /= P->rtk;
    35. 

  35. 	t = sqrt(1. - xy.y * xy.y);
    36. 

  36. 	lp.phi = asin(xy.y * P->sinphi + t * P->cosphi * (s = sin(xy.x)));
    37. 

  37. 	lp.lam = atan2(t * P->sinphi * s - xy.y * P->cosphi,
    38. 

  38. 		t * cos(xy.x));
    39. 

  39. 	return (lp);
    40. 

  40. }
    41. 

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

  42. ENTRY0(ocea)
    43. 

  43. 	double phi_0=0.0, phi_1, phi_2, lam_1, lam_2, lonz, alpha;
    44. 

  44. 

  45. 	P->rok = P->a / P->k0;
    46. 

  46. 	P->rtk = P->a * P->k0;
    47. 

  47. 	if ( pj_param(P->params, "talpha").i) {
    48. 

  48. 		alpha	= pj_param(P->params, "ralpha").f;
    49. 

  49. 		lonz = pj_param(P->params, "rlonc").f;
    50. 

  50. 		P->singam = atan(-cos(alpha)/(-sin(phi_0) * sin(alpha))) + lonz;
    51. 

  51. 		P->sinphi = asin(cos(phi_0) * sin(alpha));
    52. 

  52. 	} else {
    53. 

  53. 		phi_1 = pj_param(P->params, "rlat_1").f;
    54. 

  54. 		phi_2 = pj_param(P->params, "rlat_2").f;
    55. 

  55. 		lam_1 = pj_param(P->params, "rlon_1").f;
    56. 

  56. 		lam_2 = pj_param(P->params, "rlon_2").f;
    57. 

  57. 		P->singam = atan2(cos(phi_1) * sin(phi_2) * cos(lam_1) -
    58. 

  58. 			sin(phi_1) * cos(phi_2) * cos(lam_2),
    59. 

  59. 			sin(phi_1) * cos(phi_2) * sin(lam_2) -
    60. 

  60. 			cos(phi_1) * sin(phi_2) * sin(lam_1) );
    61. 

  61. 		P->sinphi = atan(-cos(P->singam - lam_1) / tan(phi_1));
    62. 

  62. 	}
    63. 

  63. 	P->lam0 = P->singam + HALFPI;
    64. 

  64. 	P->cosphi = cos(P->sinphi);
    65. 

  65. 	P->sinphi = sin(P->sinphi);
    66. 

  66. 	P->cosgam = cos(P->singam);
    67. 

  67. 	P->singam = sin(P->singam);
    68. 

  68. 	P->inv = s_inverse;
    69. 

  69. 	P->fwd = s_forward;
    70. 

  70. 	P->es = 0.;
    71. 

  71. ENDENTRY(P)
    72.