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#define PJ_LIB__
#include <projects.h>
#include <string.h>
struct pj_opaque {
struct PJconsts *link;
double lamp;
double cphip, sphip;
};
PROJ_HEAD(ob_tran, "General Oblique Transformation") "\n\tMisc Sph"
"\n\to_proj= plus parameters for projection"
"\n\to_lat_p= o_lon_p= (new pole) or"
"\n\to_alpha= o_lon_c= o_lat_c= or"
"\n\to_lon_1= o_lat_1= o_lon_2= o_lat_2=";
#define TOL 1e-10
static XY o_forward(LP lp, PJ *P) { /* spheroid */
struct pj_opaque *Q = P->opaque;
double coslam, sinphi, cosphi;
coslam = cos(lp.lam);
sinphi = sin(lp.phi);
cosphi = cos(lp.phi);
lp.lam = adjlon(aatan2(cosphi * sin(lp.lam), Q->sphip * cosphi * coslam +
Q->cphip * sinphi) + Q->lamp);
lp.phi = aasin(P->ctx,Q->sphip * sinphi - Q->cphip * cosphi * coslam);
return Q->link->fwd(lp, Q->link);
}
static XY t_forward(LP lp, PJ *P) { /* spheroid */
struct pj_opaque *Q = P->opaque;
double cosphi, coslam;
cosphi = cos(lp.phi);
coslam = cos(lp.lam);
lp.lam = adjlon(aatan2(cosphi * sin(lp.lam), sin(lp.phi)) + Q->lamp);
lp.phi = aasin(P->ctx, - cosphi * coslam);
return Q->link->fwd(lp, Q->link);
}
static LP o_inverse(XY xy, PJ *P) { /* spheroid */
LP lp = {0.0,0.0};
struct pj_opaque *Q = P->opaque;
double coslam, sinphi, cosphi;
lp = Q->link->inv(xy, Q->link);
if (lp.lam != HUGE_VAL) {
coslam = cos(lp.lam -= Q->lamp);
sinphi = sin(lp.phi);
cosphi = cos(lp.phi);
lp.phi = aasin(P->ctx,Q->sphip * sinphi + Q->cphip * cosphi * coslam);
lp.lam = aatan2(cosphi * sin(lp.lam), Q->sphip * cosphi * coslam -
Q->cphip * sinphi);
}
return lp;
}
static LP t_inverse(XY xy, PJ *P) { /* spheroid */
LP lp = {0.0,0.0};
struct pj_opaque *Q = P->opaque;
double cosphi, t;
lp = Q->link->inv(xy, Q->link);
if (lp.lam != HUGE_VAL) {
cosphi = cos(lp.phi);
t = lp.lam - Q->lamp;
lp.lam = aatan2(cosphi * sin(t), - sin(lp.phi));
lp.phi = aasin(P->ctx,cosphi * cos(t));
}
return lp;
}
static void *freeup_new (PJ *P) { /* Destructor */
if (0==P)
return 0;
if (0==P->opaque)
return pj_dealloc (P);
if (P->opaque->link)
return pj_dealloc (P->opaque->link);
pj_dealloc (P->opaque);
return pj_dealloc(P);
}
static void freeup (PJ *P) {
freeup_new (P);
return;
}
PJ *PROJECTION(ob_tran) {
int i;
double phip;
char *name, *s;
struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
if (0==Q)
return freeup_new (P);
P->opaque = Q;
/* get name of projection to be translated */
if (!(name = pj_param(P->ctx, P->params, "so_proj").s)) E_ERROR(-26);
for (i = 0; (s = pj_list[i].id) && strcmp(name, s) ; ++i) ;
if (!s || !(Q->link = (*pj_list[i].proj)(0))) E_ERROR(-37);
/* copy existing header into new */
P->es = 0.; /* force to spherical */
Q->link->params = P->params;
Q->link->ctx = P->ctx;
Q->link->over = P->over;
Q->link->geoc = P->geoc;
Q->link->a = P->a;
Q->link->es = P->es;
Q->link->ra = P->ra;
Q->link->lam0 = P->lam0;
Q->link->phi0 = P->phi0;
Q->link->x0 = P->x0;
Q->link->y0 = P->y0;
Q->link->k0 = P->k0;
/* force spherical earth */
Q->link->one_es = Q->link->rone_es = 1.;
Q->link->es = Q->link->e = 0.;
if (!(Q->link = pj_list[i].proj(Q->link))) {
return freeup_new(P);
}
if (pj_param(P->ctx, P->params, "to_alpha").i) {
double lamc, phic, alpha;
lamc = pj_param(P->ctx, P->params, "ro_lon_c").f;
phic = pj_param(P->ctx, P->params, "ro_lat_c").f;
alpha = pj_param(P->ctx, P->params, "ro_alpha").f;
/*
if (fabs(phic) <= TOL ||
fabs(fabs(phic) - HALFPI) <= TOL ||
fabs(fabs(alpha) - HALFPI) <= TOL)
*/
if (fabs(fabs(phic) - M_HALFPI) <= TOL)
E_ERROR(-32);
Q->lamp = lamc + aatan2(-cos(alpha), -sin(alpha) * sin(phic));
phip = aasin(P->ctx,cos(phic) * sin(alpha));
} else if (pj_param(P->ctx, P->params, "to_lat_p").i) { /* specified new pole */
Q->lamp = pj_param(P->ctx, P->params, "ro_lon_p").f;
phip = pj_param(P->ctx, P->params, "ro_lat_p").f;
} else { /* specified new "equator" points */
double lam1, lam2, phi1, phi2, con;
lam1 = pj_param(P->ctx, P->params, "ro_lon_1").f;
phi1 = pj_param(P->ctx, P->params, "ro_lat_1").f;
lam2 = pj_param(P->ctx, P->params, "ro_lon_2").f;
phi2 = pj_param(P->ctx, P->params, "ro_lat_2").f;
if (fabs(phi1 - phi2) <= TOL ||
(con = fabs(phi1)) <= TOL ||
fabs(con - M_HALFPI) <= TOL ||
fabs(fabs(phi2) - M_HALFPI) <= TOL) E_ERROR(-33);
Q->lamp = atan2(cos(phi1) * sin(phi2) * cos(lam1) -
sin(phi1) * cos(phi2) * cos(lam2),
sin(phi1) * cos(phi2) * sin(lam2) -
cos(phi1) * sin(phi2) * sin(lam1));
phip = atan(-cos(Q->lamp - lam1) / tan(phi1));
}
if (fabs(phip) > TOL) { /* oblique */
Q->cphip = cos(phip);
Q->sphip = sin(phip);
P->fwd = o_forward;
P->inv = Q->link->inv ? o_inverse : 0;
} else { /* transverse */
P->fwd = t_forward;
P->inv = Q->link->inv ? t_inverse : 0;
}
return P;
}
#ifndef PJ_SELFTEST
int pj_ob_tran_selftest (void) {return 0;}
#else
int pj_ob_tran_selftest (void) {
double tolerance_lp = 1e-10;
double tolerance_xy = 1e-7;
char s_args[] = {"+proj=ob_tran +a=6400000 +o_proj=latlon +o_lon_p=20 +o_lat_p=20 +lon_0=180"};
LP fwd_in[] = {
{ 2, 1},
{ 2,-1},
{-2, 1},
{-2,-1}
};
XY s_fwd_expect[] = {
{-2.6856872138416592, 1.2374302350496296},
{-2.6954069748943286, 1.2026833954513816},
{-2.8993663925401947, 1.2374302350496296},
{-2.8896466314875244, 1.2026833954513816},
};
XY inv_in[] = {
{ 200, 100},
{ 200,-100},
{-200, 100},
{-200,-100}
};
LP s_inv_expect[] = {
{ 121.5518748407577, -2.5361001573966084},
{ 63.261184340201858, 17.585319578673531},
{-141.10073322351622, 26.091712304855108},
{-65.862385598848391, 51.830295078417215},
};
return pj_generic_selftest (0, s_args, tolerance_xy, tolerance_lp, 4, 4, fwd_in, 0, s_fwd_expect, inv_in, 0, s_inv_expect);
}
#endif
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