src/projections/PJ_wag2.cpp


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#define PJ_LIB__

#include <math.h>

#include "projects.h"

PROJ_HEAD(wag2, "Wagner II") "\n\tPCyl, Sph";

#define C_x 0.92483
#define C_y 1.38725
#define C_p1 0.88022
#define C_p2 0.88550


static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
    XY xy = {0.0,0.0};
	lp.phi = aasin (P->ctx,C_p1 * sin (C_p2 * lp.phi));
	xy.x = C_x * lp.lam * cos (lp.phi);
	xy.y = C_y * lp.phi;
	return (xy);
}


static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
    LP lp = {0.0,0.0};
	lp.phi = xy.y / C_y;
	lp.lam = xy.x / (C_x * cos(lp.phi));
	lp.phi = aasin (P->ctx,sin(lp.phi) / C_p1) / C_p2;
	return (lp);
}


PJ *PROJECTION(wag2) {
    P->es = 0.;
    P->inv = s_inverse;
    P->fwd = s_forward;
    return P;
}