/Proj4/PJ_lsat.c
C | 174 lines | 169 code | 4 blank | 1 comment | 30 complexity | 97e211823d8d045e8a79bbf58880a50c MD5 | raw file
- #ifndef lint
- static const char SCCSID[]="@(#)PJ_lsat.c 4.1 94/02/15 GIE REL";
- #endif
- /* based upon Snyder and Linck, USGS-NMD */
- #define PROJ_PARMS__ \
- double a2, a4, b, c1, c3; \
- double q, t, u, w, p22, sa, ca, xj, rlm, rlm2;
- #define PJ_LIB__
- #include "projects.h"
- PROJ_HEAD(lsat, "Space oblique for LANDSAT")
- "\n\tCyl, Sph&Ell\n\tlsat= path=";
- #define TOL 1e-7
- #define PI_HALFPI 4.71238898038468985766
- #define TWOPI_HALFPI 7.85398163397448309610
- static void
- seraz0(double lam, double mult, PJ *P) {
- double sdsq, h, s, fc, sd, sq, d__1;
- lam *= DEG_TO_RAD;
- sd = sin(lam);
- sdsq = sd * sd;
- s = P->p22 * P->sa * cos(lam) * sqrt((1. + P->t * sdsq) / ((
- 1. + P->w * sdsq) * (1. + P->q * sdsq)));
- d__1 = 1. + P->q * sdsq;
- h = sqrt((1. + P->q * sdsq) / (1. + P->w * sdsq)) * ((1. +
- P->w * sdsq) / (d__1 * d__1) - P->p22 * P->ca);
- sq = sqrt(P->xj * P->xj + s * s);
- P->b += fc = mult * (h * P->xj - s * s) / sq;
- P->a2 += fc * cos(lam + lam);
- P->a4 += fc * cos(lam * 4.);
- fc = mult * s * (h + P->xj) / sq;
- P->c1 += fc * cos(lam);
- P->c3 += fc * cos(lam * 3.);
- }
- FORWARD(e_forward); /* ellipsoid */
- int l, nn;
- double lamt, xlam, sdsq, c, d, s, lamdp, phidp, lampp, tanph,
- lamtp, cl, sd, sp, fac, sav, tanphi;
- if (lp.phi > HALFPI)
- lp.phi = HALFPI;
- else if (lp.phi < -HALFPI)
- lp.phi = -HALFPI;
- lampp = lp.phi >= 0. ? HALFPI : PI_HALFPI;
- tanphi = tan(lp.phi);
- for (nn = 0;;) {
- sav = lampp;
- lamtp = lp.lam + P->p22 * lampp;
- cl = cos(lamtp);
- if (fabs(cl) < TOL)
- lamtp -= TOL;
- fac = lampp - sin(lampp) * (cl < 0. ? -HALFPI : HALFPI);
- for (l = 50; l; --l) {
- lamt = lp.lam + P->p22 * sav;
- if (fabs(c = cos(lamt)) < TOL)
- lamt -= TOL;
- xlam = (P->one_es * tanphi * P->sa + sin(lamt) * P->ca) / c;
- lamdp = atan(xlam) + fac;
- if (fabs(fabs(sav) - fabs(lamdp)) < TOL)
- break;
- sav = lamdp;
- }
- if (!l || ++nn >= 3 || (lamdp > P->rlm && lamdp < P->rlm2))
- break;
- if (lamdp <= P->rlm)
- lampp = TWOPI_HALFPI;
- else if (lamdp >= P->rlm2)
- lampp = HALFPI;
- }
- if (l) {
- sp = sin(lp.phi);
- phidp = aasin((P->one_es * P->ca * sp - P->sa * cos(lp.phi) *
- sin(lamt)) / sqrt(1. - P->es * sp * sp));
- tanph = log(tan(FORTPI + .5 * phidp));
- sd = sin(lamdp);
- sdsq = sd * sd;
- s = P->p22 * P->sa * cos(lamdp) * sqrt((1. + P->t * sdsq)
- / ((1. + P->w * sdsq) * (1. + P->q * sdsq)));
- d = sqrt(P->xj * P->xj + s * s);
- xy.x = P->b * lamdp + P->a2 * sin(2. * lamdp) + P->a4 *
- sin(lamdp * 4.) - tanph * s / d;
- xy.y = P->c1 * sd + P->c3 * sin(lamdp * 3.) + tanph * P->xj / d;
- } else
- xy.x = xy.y = HUGE_VAL;
- return xy;
- }
- INVERSE(e_inverse); /* ellipsoid */
- int nn;
- double lamt, sdsq, s, lamdp, phidp, sppsq, dd, sd, sl, fac, scl, sav, spp;
- lamdp = xy.x / P->b;
- nn = 50;
- do {
- sav = lamdp;
- sd = sin(lamdp);
- sdsq = sd * sd;
- s = P->p22 * P->sa * cos(lamdp) * sqrt((1. + P->t * sdsq)
- / ((1. + P->w * sdsq) * (1. + P->q * sdsq)));
- lamdp = xy.x + xy.y * s / P->xj - P->a2 * sin(
- 2. * lamdp) - P->a4 * sin(lamdp * 4.) - s / P->xj * (
- P->c1 * sin(lamdp) + P->c3 * sin(lamdp * 3.));
- lamdp /= P->b;
- } while (fabs(lamdp - sav) >= TOL && --nn);
- sl = sin(lamdp);
- fac = exp(sqrt(1. + s * s / P->xj / P->xj) * (xy.y -
- P->c1 * sl - P->c3 * sin(lamdp * 3.)));
- phidp = 2. * (atan(fac) - FORTPI);
- dd = sl * sl;
- if (fabs(cos(lamdp)) < TOL)
- lamdp -= TOL;
- spp = sin(phidp);
- sppsq = spp * spp;
- lamt = atan(((1. - sppsq * P->rone_es) * tan(lamdp) *
- P->ca - spp * P->sa * sqrt((1. + P->q * dd) * (
- 1. - sppsq) - sppsq * P->u) / cos(lamdp)) / (1. - sppsq
- * (1. + P->u)));
- sl = lamt >= 0. ? 1. : -1.;
- scl = cos(lamdp) >= 0. ? 1. : -1;
- lamt -= HALFPI * (1. - scl) * sl;
- lp.lam = lamt - P->p22 * lamdp;
- if (fabs(P->sa) < TOL)
- lp.phi = aasin(spp / sqrt(P->one_es * P->one_es + P->es * sppsq));
- else
- lp.phi = atan((tan(lamdp) * cos(lamt) - P->ca * sin(lamt)) /
- (P->one_es * P->sa));
- return lp;
- }
- FREEUP; if (P) pj_dalloc(P); }
- ENTRY0(lsat)
- int land, path;
- double lam, alf, esc, ess;
- land = pj_param(P->params, "ilsat").i;
- if (land <= 0 || land > 5) E_ERROR(-28);
- path = pj_param(P->params, "ipath").i;
- if (path <= 0 || path > (land <= 3 ? 251 : 233)) E_ERROR(-29);
- if (land <= 3) {
- P->lam0 = DEG_TO_RAD * 128.87 - TWOPI / 251. * path;
- P->p22 = 103.2669323;
- alf = DEG_TO_RAD * 99.092;
- } else {
- P->lam0 = DEG_TO_RAD * 129.3 - TWOPI / 233. * path;
- P->p22 = 98.8841202;
- alf = DEG_TO_RAD * 98.2;
- }
- P->p22 /= 1440.;
- P->sa = sin(alf);
- P->ca = cos(alf);
- if (fabs(P->ca) < 1e-9)
- P->ca = 1e-9;
- esc = P->es * P->ca * P->ca;
- ess = P->es * P->sa * P->sa;
- P->w = (1. - esc) * P->rone_es;
- P->w = P->w * P->w - 1.;
- P->q = ess * P->rone_es;
- P->t = ess * (2. - P->es) * P->rone_es * P->rone_es;
- P->u = esc * P->rone_es;
- P->xj = P->one_es * P->one_es * P->one_es;
- P->rlm = PI * (1. / 248. + .5161290322580645);
- P->rlm2 = P->rlm + TWOPI;
- P->a2 = P->a4 = P->b = P->c1 = P->c3 = 0.;
- seraz0(0., 1., P);
- for (lam = 9.; lam <= 81.0001; lam += 18.)
- seraz0(lam, 4., P);
- for (lam = 18; lam <= 72.0001; lam += 18.)
- seraz0(lam, 2., P);
- seraz0(90., 1., P);
- P->a2 /= 30.;
- P->a4 /= 60.;
- P->b /= 30.;
- P->c1 /= 15.;
- P->c3 /= 45.;
- P->inv = e_inverse; P->fwd = e_forward;
- ENDENTRY(P)