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Diffstat (limited to 'src/projections/misrsom.cpp')
| -rw-r--r-- | src/projections/misrsom.cpp | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/src/projections/misrsom.cpp b/src/projections/misrsom.cpp new file mode 100644 index 00000000..c84b96e3 --- /dev/null +++ b/src/projections/misrsom.cpp @@ -0,0 +1,219 @@ +/****************************************************************************** + * This implements Space Oblique Mercator (SOM) projection, used by the + * Multi-angle Imaging SpectroRadiometer (MISR) products, from the NASA EOS Terra + * platform. + * + * The code is identical to that of Landsat SOM (PJ_lsat.c) with the following + * parameter changes: + * + * inclination angle = 98.30382 degrees + * period of revolution = 98.88 minutes + * ascending longitude = 129.3056 degrees - (360 / 233) * path_number + * + * and the following code change: + * + * Q->rlm = PI * (1. / 248. + .5161290322580645); + * + * changed to: + * + * Q->rlm = 0 + * + *****************************************************************************/ +/* based upon Snyder and Linck, USGS-NMD */ +#define PJ_LIB__ + +#include <errno.h> +#include <math.h> + +#include "proj.h" +#include "projects.h" + +PROJ_HEAD(misrsom, "Space oblique for MISR") + "\n\tCyl, Sph&Ell\n\tpath="; + +#define TOL 1e-7 + +namespace { // anonymous namespace +struct pj_opaque { + double a2, a4, b, c1, c3; + double q, t, u, w, p22, sa, ca, xj, rlm, rlm2; +}; +} // anonymous namespace + +static void seraz0(double lam, double mult, PJ *P) { + struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque); + double sdsq, h, s, fc, sd, sq, d__1; + + lam *= DEG_TO_RAD; + sd = sin(lam); + sdsq = sd * sd; + s = Q->p22 * Q->sa * cos(lam) * sqrt((1. + Q->t * sdsq) / (( + 1. + Q->w * sdsq) * (1. + Q->q * sdsq))); + d__1 = 1. + Q->q * sdsq; + h = sqrt((1. + Q->q * sdsq) / (1. + Q->w * sdsq)) * ((1. + + Q->w * sdsq) / (d__1 * d__1) - Q->p22 * Q->ca); + sq = sqrt(Q->xj * Q->xj + s * s); + Q->b += fc = mult * (h * Q->xj - s * s) / sq; + Q->a2 += fc * cos(lam + lam); + Q->a4 += fc * cos(lam * 4.); + fc = mult * s * (h + Q->xj) / sq; + Q->c1 += fc * cos(lam); + Q->c3 += fc * cos(lam * 3.); +} + + +static XY e_forward (LP lp, PJ *P) { /* Ellipsoidal, forward */ + XY xy = {0.0,0.0}; + struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque); + int l, nn; + double lamt = 0.0, xlam, sdsq, c, d, s, lamdp = 0.0, phidp, lampp, tanph; + double lamtp, cl, sd, sp, sav, tanphi; + + if (lp.phi > M_HALFPI) + lp.phi = M_HALFPI; + else if (lp.phi < -M_HALFPI) + lp.phi = -M_HALFPI; + if (lp.phi >= 0. ) + lampp = M_HALFPI; + else + lampp = M_PI_HALFPI; + tanphi = tan(lp.phi); + for (nn = 0;;) { + double fac; + sav = lampp; + lamtp = lp.lam + Q->p22 * lampp; + cl = cos(lamtp); + if( cl < 0 ) + fac = lampp + sin(lampp) * M_HALFPI; + else + fac = lampp - sin(lampp) * M_HALFPI; + for (l = 50; l; --l) { + lamt = lp.lam + Q->p22 * sav; + if (fabs(c = cos(lamt)) < TOL) + lamt -= TOL; + xlam = (P->one_es * tanphi * Q->sa + sin(lamt) * Q->ca) / c; + lamdp = atan(xlam) + fac; + if (fabs(fabs(sav) - fabs(lamdp)) < TOL) + break; + sav = lamdp; + } + if (!l || ++nn >= 3 || (lamdp > Q->rlm && lamdp < Q->rlm2)) + break; + if (lamdp <= Q->rlm) + lampp = M_TWOPI_HALFPI; + else if (lamdp >= Q->rlm2) + lampp = M_HALFPI; + } + if (l) { + sp = sin(lp.phi); + phidp = aasin(P->ctx,(P->one_es * Q->ca * sp - Q->sa * cos(lp.phi) * + sin(lamt)) / sqrt(1. - P->es * sp * sp)); + tanph = log(tan(M_FORTPI + .5 * phidp)); + sd = sin(lamdp); + sdsq = sd * sd; + s = Q->p22 * Q->sa * cos(lamdp) * sqrt((1. + Q->t * sdsq) + / ((1. + Q->w * sdsq) * (1. + Q->q * sdsq))); + d = sqrt(Q->xj * Q->xj + s * s); + xy.x = Q->b * lamdp + Q->a2 * sin(2. * lamdp) + Q->a4 * + sin(lamdp * 4.) - tanph * s / d; + xy.y = Q->c1 * sd + Q->c3 * sin(lamdp * 3.) + tanph * Q->xj / d; + } else + xy.x = xy.y = HUGE_VAL; + return xy; +} + + +static LP e_inverse (XY xy, PJ *P) { /* Ellipsoidal, inverse */ + LP lp = {0.0,0.0}; + struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque); + int nn; + double lamt, sdsq, s, lamdp, phidp, sppsq, dd, sd, sl, fac, scl, sav, spp; + + lamdp = xy.x / Q->b; + nn = 50; + do { + sav = lamdp; + sd = sin(lamdp); + sdsq = sd * sd; + s = Q->p22 * Q->sa * cos(lamdp) * sqrt((1. + Q->t * sdsq) + / ((1. + Q->w * sdsq) * (1. + Q->q * sdsq))); + lamdp = xy.x + xy.y * s / Q->xj - Q->a2 * sin( + 2. * lamdp) - Q->a4 * sin(lamdp * 4.) - s / Q->xj * ( + Q->c1 * sin(lamdp) + Q->c3 * sin(lamdp * 3.)); + lamdp /= Q->b; + } while (fabs(lamdp - sav) >= TOL && --nn); + sl = sin(lamdp); + fac = exp(sqrt(1. + s * s / Q->xj / Q->xj) * (xy.y - + Q->c1 * sl - Q->c3 * sin(lamdp * 3.))); + phidp = 2. * (atan(fac) - M_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) * + Q->ca - spp * Q->sa * sqrt((1. + Q->q * dd) * ( + 1. - sppsq) - sppsq * Q->u) / cos(lamdp)) / (1. - sppsq + * (1. + Q->u))); + sl = lamt >= 0. ? 1. : -1.; + scl = cos(lamdp) >= 0. ? 1. : -1; + lamt -= M_HALFPI * (1. - scl) * sl; + lp.lam = lamt - Q->p22 * lamdp; + if (fabs(Q->sa) < TOL) + lp.phi = aasin(P->ctx,spp / sqrt(P->one_es * P->one_es + P->es * sppsq)); + else + lp.phi = atan((tan(lamdp) * cos(lamt) - Q->ca * sin(lamt)) / + (P->one_es * Q->sa)); + return lp; +} + + +PJ *PROJECTION(misrsom) { + int path; + double lam, alf, esc, ess; + + struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque))); + if (nullptr==Q) + return pj_default_destructor (P, ENOMEM); + P->opaque = Q; + + path = pj_param(P->ctx, P->params, "ipath").i; + if (path <= 0 || path > 233) + return pj_default_destructor(P, PJD_ERR_PATH_NOT_IN_RANGE); + + P->lam0 = DEG_TO_RAD * 129.3056 - M_TWOPI / 233. * path; + alf = 98.30382 * DEG_TO_RAD; + Q->p22 = 98.88 / 1440.0; + + Q->sa = sin(alf); + Q->ca = cos(alf); + if (fabs(Q->ca) < 1e-9) + Q->ca = 1e-9; + esc = P->es * Q->ca * Q->ca; + ess = P->es * Q->sa * Q->sa; + Q->w = (1. - esc) * P->rone_es; + Q->w = Q->w * Q->w - 1.; + Q->q = ess * P->rone_es; + Q->t = ess * (2. - P->es) * P->rone_es * P->rone_es; + Q->u = esc * P->rone_es; + Q->xj = P->one_es * P->one_es * P->one_es; + Q->rlm = 0; + Q->rlm2 = Q->rlm + M_TWOPI; + Q->a2 = Q->a4 = Q->b = Q->c1 = Q->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); + Q->a2 /= 30.; + Q->a4 /= 60.; + Q->b /= 30.; + Q->c1 /= 15.; + Q->c3 /= 45.; + + P->inv = e_inverse; + P->fwd = e_forward; + + return P; +} |