diff options
Diffstat (limited to 'src/PJ_wink2.cpp')
| -rw-r--r-- | src/PJ_wink2.cpp | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/PJ_wink2.cpp b/src/PJ_wink2.cpp new file mode 100644 index 00000000..9da65eaa --- /dev/null +++ b/src/PJ_wink2.cpp @@ -0,0 +1,52 @@ +#define PJ_LIB__ + +#include <errno.h> +#include <math.h> + +#include "projects.h" + +PROJ_HEAD(wink2, "Winkel II") "\n\tPCyl, Sph, no inv\n\tlat_1="; + +struct pj_opaque { double cosphi1; }; + +#define MAX_ITER 10 +#define LOOP_TOL 1e-7 + + +static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */ + XY xy = {0.0, 0.0}; + double k, V; + int i; + + xy.y = lp.phi * M_TWO_D_PI; + k = M_PI * sin (lp.phi); + lp.phi *= 1.8; + for (i = MAX_ITER; i ; --i) { + lp.phi -= V = (lp.phi + sin (lp.phi) - k) / + (1. + cos (lp.phi)); + if (fabs (V) < LOOP_TOL) + break; + } + if (!i) + lp.phi = (lp.phi < 0.) ? -M_HALFPI : M_HALFPI; + else + lp.phi *= 0.5; + xy.x = 0.5 * lp.lam * (cos (lp.phi) + static_cast<struct pj_opaque*>(P->opaque)->cosphi1); + xy.y = M_FORTPI * (sin (lp.phi) + xy.y); + return xy; +} + + +PJ *PROJECTION(wink2) { + struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque))); + if (0==Q) + return pj_default_destructor(P, ENOMEM); + P->opaque = Q; + + static_cast<struct pj_opaque*>(P->opaque)->cosphi1 = cos(pj_param(P->ctx, P->params, "rlat_1").f); + P->es = 0.; + P->inv = 0; + P->fwd = s_forward; + + return P; +} |
