PJ_loxim.c
1.12 KB
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#ifndef lint
static const char SCCSID[]="@(#)PJ_loxim.c 4.1 94/02/15 GIE REL";
#endif
#define PROJ_PARMS__ \
double phi1; \
double cosphi1; \
double tanphi1;
#define PJ_LIB__
#include "projects.h"
PROJ_HEAD(loxim, "Loximuthal") "\n\tPCyl Sph";
#define EPS 1e-8
FORWARD(s_forward); /* spheroid */
xy.y = lp.phi - P->phi1;
if (fabs(xy.y) < EPS)
xy.x = lp.lam * P->cosphi1;
else {
xy.x = FORTPI + 0.5 * lp.phi;
if (fabs(xy.x) < EPS || fabs(fabs(xy.x) - HALFPI) < EPS)
xy.x = 0.;
else
xy.x = lp.lam * xy.y / log( tan(xy.x) / P->tanphi1 );
}
return (xy);
}
INVERSE(s_inverse); /* spheroid */
lp.phi = xy.y + P->phi1;
if (fabs(xy.y) < EPS)
lp.lam = xy.x / P->cosphi1;
else
if (fabs( lp.lam = FORTPI + 0.5 * lp.phi ) < EPS ||
fabs(fabs(lp.lam) - HALFPI) < EPS)
lp.lam = 0.;
else
lp.lam = xy.x * log( tan(lp.lam) / P->tanphi1 ) / xy.y ;
return (lp);
}
FREEUP; if (P) pj_dalloc(P); }
ENTRY0(loxim);
P->phi1 = pj_param(P->params, "rlat_1").f;
if ((P->cosphi1 = cos(P->phi1)) < EPS) E_ERROR(-22);
P->tanphi1 = tan(FORTPI + 0.5 * P->phi1);
P->inv = s_inverse; P->fwd = s_forward;
P->es = 0.;
ENDENTRY(P)