/Proj4/PJ_eqdc.c

http://github.com/route-me/route-me · C · 88 lines · 85 code · 3 blank · 0 comment · 13 complexity · bd8122eb944b6dd05bb9583a0fa45a1f MD5 · raw file 

    

  1. #ifndef lint
    2. 

  2. static const char SCCSID[]="@(#)PJ_eqdc.c	4.2	94/03/16	GIE	REL";
    3. 

  3. #endif
    4. 

  4. #define PROJ_PARMS__ \
    5. 

  5. 	double phi1; \
    6. 

  6. 	double phi2; \
    7. 

  7. 	double n; \
    8. 

  8. 	double rho; \
    9. 

  9. 	double rho0; \
    10. 

  10. 	double c; \
    11. 

  11. 	double *en; \
    12. 

  12. 	int		ellips;
    13. 

  13. #define PJ_LIB__
    14. 

  14. #include	"projects.h"
    15. 

  15. PROJ_HEAD(eqdc, "Equidistant Conic")
    16. 

  16. 	"\n\tConic, Sph&Ell\n\tlat_1= lat_2=";
    17. 

  17. # define EPS10	1.e-10
    18. 

  18. FORWARD(e_forward); /* sphere & ellipsoid */
    19. 

  19. 	P->rho = P->c - (P->ellips ? pj_mlfn(lp.phi, sin(lp.phi),
    20. 

  20. 		cos(lp.phi), P->en) : lp.phi);
    21. 

  21. 	xy.x = P->rho * sin( lp.lam *= P->n );
    22. 

  22. 	xy.y = P->rho0 - P->rho * cos(lp.lam);
    23. 

  23. 	return (xy);
    24. 

  24. }
    25. 

  25. INVERSE(e_inverse); /* sphere & ellipsoid */
    26. 

  26. 	if ((P->rho = hypot(xy.x, xy.y = P->rho0 - xy.y)) != 0.0 ) {
    27. 

  27. 		if (P->n < 0.) {
    28. 

  28. 			P->rho = -P->rho;
    29. 

  29. 			xy.x = -xy.x;
    30. 

  30. 			xy.y = -xy.y;
    31. 

  31. 		}
    32. 

  32. 		lp.phi = P->c - P->rho;
    33. 

  33. 		if (P->ellips)
    34. 

  34. 			lp.phi = pj_inv_mlfn(lp.phi, P->es, P->en);
    35. 

  35. 		lp.lam = atan2(xy.x, xy.y) / P->n;
    36. 

  36. 	} else {
    37. 

  37. 		lp.lam = 0.;
    38. 

  38. 		lp.phi = P->n > 0. ? HALFPI : - HALFPI;
    39. 

  39. 	}
    40. 

  40. 	return (lp);
    41. 

  41. }
    42. 

  42. SPECIAL(fac) {
    43. 

  43. 	double sinphi, cosphi;
    44. 

  44. 

  45. 	sinphi = sin(lp.phi);
    46. 

  46. 	cosphi = cos(lp.phi);
    47. 

  47. 	fac->code |= IS_ANAL_HK;
    48. 

  48. 	fac->h = 1.;
    49. 

  49. 	fac->k = P->n * (P->c - (P->ellips ? pj_mlfn(lp.phi, sinphi,
    50. 

  50. 		cosphi, P->en) : lp.phi)) / pj_msfn(sinphi, cosphi, P->es);
    51. 

  51. }
    52. 

  52. FREEUP; if (P) { if (P->en) pj_dalloc(P->en); pj_dalloc(P); } }
    53. 

  53. ENTRY1(eqdc, en)
    54. 

  54. 	double cosphi, sinphi;
    55. 

  55. 	int secant;
    56. 

  56. 

  57. 	P->phi1 = pj_param(P->params, "rlat_1").f;
    58. 

  58. 	P->phi2 = pj_param(P->params, "rlat_2").f;
    59. 

  59. 	if (fabs(P->phi1 + P->phi2) < EPS10) E_ERROR(-21);
    60. 

  60. 	if (!(P->en = pj_enfn(P->es)))
    61. 

  61. 		E_ERROR_0;
    62. 

  62. 	P->n = sinphi = sin(P->phi1);
    63. 

  63. 	cosphi = cos(P->phi1);
    64. 

  64. 	secant = fabs(P->phi1 - P->phi2) >= EPS10;
    65. 

  65. 	if( (P->ellips = (P->es > 0.)) ) {
    66. 

  66. 		double ml1, m1;
    67. 

  67. 

  68. 		m1 = pj_msfn(sinphi, cosphi, P->es);
    69. 

  69. 		ml1 = pj_mlfn(P->phi1, sinphi, cosphi, P->en);
    70. 

  70. 		if (secant) { /* secant cone */
    71. 

  71. 			sinphi = sin(P->phi2);
    72. 

  72. 			cosphi = cos(P->phi2);
    73. 

  73. 			P->n = (m1 - pj_msfn(sinphi, cosphi, P->es)) /
    74. 

  74. 				(pj_mlfn(P->phi2, sinphi, cosphi, P->en) - ml1);
    75. 

  75. 		}
    76. 

  76. 		P->c = ml1 + m1 / P->n;
    77. 

  77. 		P->rho0 = P->c - pj_mlfn(P->phi0, sin(P->phi0),
    78. 

  78. 			cos(P->phi0), P->en);
    79. 

  79. 	} else {
    80. 

  80. 		if (secant)
    81. 

  81. 			P->n = (cosphi - cos(P->phi2)) / (P->phi2 - P->phi1);
    82. 

  82. 		P->c = P->phi1 + cos(P->phi1) / P->n;
    83. 

  83. 		P->rho0 = P->c - P->phi0;
    84. 

  84. 	}
    85. 

  85. 	P->inv = e_inverse;
    86. 

  86. 	P->fwd = e_forward;
    87. 

  87. 	P->spc = fac;
    88. 

  88. ENDENTRY(P)
    89.