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#define PJ_LIB__
#include <projects.h>
PROJ_HEAD(merc, "Mercator") "\n\tCyl, Sph&Ell\n\tlat_ts=";
#define EPS10 1.e-10
static XY e_forward (LP lp, PJ *P) { /* Ellipsoidal, forward */
XY xy = {0.0,0.0};
if (fabs(fabs(lp.phi) - M_HALFPI) <= EPS10)
F_ERROR;
xy.x = P->k0 * lp.lam;
xy.y = - P->k0 * log(pj_tsfn(lp.phi, sin(lp.phi), P->e));
return xy;
}
static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */
XY xy = {0.0,0.0};
if (fabs(fabs(lp.phi) - M_HALFPI) <= EPS10)
F_ERROR;
xy.x = P->k0 * lp.lam;
xy.y = P->k0 * log(tan(M_FORTPI + .5 * lp.phi));
return xy;
}
static LP e_inverse (XY xy, PJ *P) { /* Ellipsoidal, inverse */
LP lp = {0.0,0.0};
if ((lp.phi = pj_phi2(P->ctx, exp(- xy.y / P->k0), P->e)) == HUGE_VAL)
I_ERROR;
lp.lam = xy.x / P->k0;
return lp;
}
static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */
LP lp = {0.0,0.0};
lp.phi = M_HALFPI - 2. * atan(exp(-xy.y / P->k0));
lp.lam = xy.x / P->k0;
return lp;
}
static void freeup(PJ *P) { /* Destructor */
pj_dealloc(P);
}
PJ *PROJECTION(merc) {
double phits=0.0;
int is_phits;
if( (is_phits = pj_param(P->ctx, P->params, "tlat_ts").i) ) {
phits = fabs(pj_param(P->ctx, P->params, "rlat_ts").f);
if (phits >= M_HALFPI) E_ERROR(-24);
}
if (P->es) { /* ellipsoid */
if (is_phits)
P->k0 = pj_msfn(sin(phits), cos(phits), P->es);
P->inv = e_inverse;
P->fwd = e_forward;
}
else { /* sphere */
if (is_phits)
P->k0 = cos(phits);
P->inv = s_inverse;
P->fwd = s_forward;
}
return P;
}
#ifndef PJ_SELFTEST
int pj_merc_selftest (void) {return 0;}
#else
int pj_merc_selftest (void) {
double tolerance_lp = 1e-10;
double tolerance_xy = 1e-7;
char e_args[] = {"+proj=merc +ellps=GRS80 +lat_1=0.5 +lat_2=2"};
char s_args[] = {"+proj=merc +a=6400000 +lat_1=0.5 +lat_2=2"};
LP fwd_in[] = {
{ 2, 1},
{ 2,-1},
{-2, 1},
{-2,-1}
};
XY e_fwd_expect[] = {
{ 222638.981586547132, 110579.965218249708},
{ 222638.981586547132, -110579.965218249112},
{-222638.981586547132, 110579.965218249708},
{-222638.981586547132, -110579.965218249112},
};
XY s_fwd_expect[] = {
{ 223402.144255274179, 111706.743574944077},
{ 223402.144255274179, -111706.743574944485},
{-223402.144255274179, 111706.743574944077},
{-223402.144255274179, -111706.743574944485},
};
XY inv_in[] = {
{ 200, 100},
{ 200,-100},
{-200, 100},
{-200,-100}
};
LP e_inv_expect[] = {
{ 0.00179663056823904264, 0.00090436947522799056},
{ 0.00179663056823904264, -0.00090436947522799056},
{-0.00179663056823904264, 0.00090436947522799056},
{-0.00179663056823904264, -0.00090436947522799056},
};
LP s_inv_expect[] = {
{ 0.00179049310978382265, 0.000895246554845297135},
{ 0.00179049310978382265, -0.000895246554858019272},
{-0.00179049310978382265, 0.000895246554845297135},
{-0.00179049310978382265, -0.000895246554858019272},
};
return pj_generic_selftest (e_args, s_args, tolerance_xy, tolerance_lp, 4, 4, fwd_in, e_fwd_expect, s_fwd_expect, inv_in, e_inv_expect, s_inv_expect);
}
#endif
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