svn-gvsig-desktop / tags / v1_9_Build_1230 / libraries / libjni-proj4 / src / PJ_tpeqd.c @ 33666
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#ifndef lint
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static const char SCCSID[]="@(#)PJ_tpeqd.c 4.1 94/02/15 GIE REL"; |
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#endif
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#define PROJ_PARMS__ \
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double cp1, sp1, cp2, sp2, ccs, cs, sc, r2z0, z02, dlam2; \
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double hz0, thz0, rhshz0, ca, sa, lp, lamc;
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#define PJ_LIB__
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#include <projects.h> |
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PROJ_HEAD(tpeqd, "Two Point Equidistant")
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"\n\tMisc Sph\n\tlat_1= lon_1= lat_2= lon_2=";
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FORWARD(s_forward); /* sphere */
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double t, z1, z2, dl1, dl2, sp, cp;
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sp = sin(lp.phi); |
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cp = cos(lp.phi); |
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z1 = aacos(P->sp1 * sp + P->cp1 * cp * cos(dl1 = lp.lam + P->dlam2)); |
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z2 = aacos(P->sp2 * sp + P->cp2 * cp * cos(dl2 = lp.lam - P->dlam2)); |
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z1 *= z1; |
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z2 *= z2; |
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xy.x = P->r2z0 * (t = z1 - z2); |
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t = P->z02 - t; |
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xy.y = P->r2z0 * asqrt(4. * P->z02 * z2 - t * t);
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if ((P->ccs * sp - cp * (P->cs * sin(dl1) - P->sc * sin(dl2))) < 0.) |
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xy.y = -xy.y; |
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return xy;
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} |
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INVERSE(s_inverse); /* sphere */
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double cz1, cz2, s, d, cp, sp;
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cz1 = cos(hypot(xy.y, xy.x + P->hz0)); |
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cz2 = cos(hypot(xy.y, xy.x - P->hz0)); |
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s = cz1 + cz2; |
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d = cz1 - cz2; |
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lp.lam = - atan2(d, (s * P->thz0)); |
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lp.phi = aacos(hypot(P->thz0 * s, d) * P->rhshz0); |
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if ( xy.y < 0. ) |
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lp.phi = - lp.phi; |
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/* lam--phi now in system relative to P1--P2 base equator */
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sp = sin(lp.phi); |
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cp = cos(lp.phi); |
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lp.phi = aasin(P->sa * sp + P->ca * cp * (s = cos(lp.lam -= P->lp))); |
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lp.lam = atan2(cp * sin(lp.lam), P->sa * cp * s - P->ca * sp) + P->lamc; |
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return lp;
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} |
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FREEUP; if (P) pj_dalloc(P); }
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ENTRY0(tpeqd) |
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double lam_1, lam_2, phi_1, phi_2, A12, pp;
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/* get control point locations */
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phi_1 = pj_param(P->params, "rlat_1").f;
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lam_1 = pj_param(P->params, "rlon_1").f;
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phi_2 = pj_param(P->params, "rlat_2").f;
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lam_2 = pj_param(P->params, "rlon_2").f;
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if (phi_1 == phi_2 && lam_1 == lam_2) E_ERROR(-25); |
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P->lam0 = adjlon(0.5 * (lam_1 + lam_2)); |
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P->dlam2 = adjlon(lam_2 - lam_1); |
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P->cp1 = cos(phi_1); |
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P->cp2 = cos(phi_2); |
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P->sp1 = sin(phi_1); |
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P->sp2 = sin(phi_2); |
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P->cs = P->cp1 * P->sp2; |
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P->sc = P->sp1 * P->cp2; |
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P->ccs = P->cp1 * P->cp2 * sin(P->dlam2); |
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P->z02 = aacos(P->sp1 * P->sp2 + P->cp1 * P->cp2 * cos(P->dlam2)); |
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P->hz0 = .5 * P->z02;
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A12 = atan2(P->cp2 * sin(P->dlam2), |
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P->cp1 * P->sp2 - P->sp1 * P->cp2 * cos(P->dlam2)); |
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P->ca = cos(pp = aasin(P->cp1 * sin(A12))); |
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P->sa = sin(pp); |
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P->lp = adjlon(atan2(P->cp1 * cos(A12), P->sp1) - P->hz0); |
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P->dlam2 *= .5;
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P->lamc = HALFPI - atan2(sin(A12) * P->sp1, cos(A12)) - P->dlam2; |
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P->thz0 = tan(P->hz0); |
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P->rhshz0 = .5 / sin(P->hz0);
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P->r2z0 = 0.5 / P->z02; |
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P->z02 *= P->z02; |
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P->inv = s_inverse; P->fwd = s_forward; |
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P->es = 0.;
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ENDENTRY(P) |