#ifndef lintstatic const char SCCSID[]="@(#)PJ_imw_p.c	4.1	94/05/22	GIE	REL";#endif#define PROJ_PARMS__ \	double	P, Pp, Q, Qp, R_1, R_2, sphi_1, sphi_2, C2; \	double	phi_1, phi_2, lam_1; \	double	*en; \	int	mode; /* = 0, phi_1 and phi_2 != 0, = 1, phi_1 = 0, = -1 phi_2 = 0 */#define PJ_LIB__#include	<projects.h>PROJ_HEAD(imw_p, "International Map of the World Polyconic")	"\n\tMod. Polyconic, Ell\n\tlat_1= and lat_2= [lon_1=]";#define TOL 1e-10#define EPS 1e-10	static intphi12(PJ *P, double *del, double *sig) {	int err = 0;	if (!pj_param(P->params, "tlat_1").i ||		!pj_param(P->params, "tlat_2").i) {		err = -41;	} else {		P->phi_1 = pj_param(P->params, "rlat_1").f;		P->phi_2 = pj_param(P->params, "rlat_2").f;		*del = 0.5 * (P->phi_2 - P->phi_1);		*sig = 0.5 * (P->phi_2 + P->phi_1);		err = (fabs(*del) < EPS || fabs(*sig) < EPS) ? -42 : 0;	}	return err;}	static XYloc_for(LP lp, PJ *P, double *yc) {	XY xy;	if (! lp.phi) {		xy.x = lp.lam;		xy.y = 0.;	} else {		double xa, ya, xb, yb, xc, yc, D, B, m, sp, t, R, C;		sp = sin(lp.phi);		m = pj_mlfn(lp.phi, sp, cos(lp.phi), P->en);		xa = P->Pp + P->Qp * m;		ya = P->P + P->Q * m;		R = 1. / (tan(lp.phi) * sqrt(1. - P->es * sp * sp));		C = sqrt(R * R - xa * xa);		if (lp.phi < 0.) C = - C;		C += ya - R;		if (P->mode < 0) {			xb = lp.lam;			yb = P->C2;		} else {			t = lp.lam * P->sphi_2;			xb = P->R_2 * sin(t);			yb = P->C2 + P->R_2 * (1. - cos(t));		}		if (P->mode > 0) {			xc = lp.lam;			yc = 0.;		} else {			t = lp.lam * P->sphi_1;			xc = P->R_1 * sin(t);			yc = P->R_1 * (1. - cos(t));		}		D = (xb - xc)/(yb - yc);		B = xc + D * (C + R - yc);		xy.x = D * sqrt(R * R * (1 + D * D) - B * B);		if (lp.phi > 0)			xy.x = - xy.x;		xy.x = (B + xy.x) / (1. + D * D);		xy.y = sqrt(R * R - xy.x * xy.x);		if (lp.phi > 0)			xy.y = - xy.y;		xy.y += C + R;	}	return (xy);}FORWARD(e_forward); /* ellipsoid */	double yc;	xy = loc_for(lp, P, &yc);	return (xy);}INVERSE(e_inverse); /* ellipsoid */	XY t;	double yc;	lp.phi = P->phi_2;	lp.lam = xy.x / cos(lp.phi);	do {		t = loc_for(lp, P, &yc);		lp.phi = ((lp.phi - P->phi_1) * (xy.y - yc) / (t.y - yc)) + P->phi_1;		lp.lam = lp.lam * xy.x / t.x;	} while (fabs(t.x - xy.x) > TOL || fabs(t.y - xy.y) > TOL);	return (lp);}	static voidxy(PJ *P, double phi, double *x, double *y, double *sp, double *R) {	double F;	*sp = sin(phi);	*R = 1./(tan(phi) * sqrt(1. - P->es * *sp * *sp ));	F = P->lam_1 * *sp;	*y = *R * (1 - cos(F));	*x = *R * sin(F);}FREEUP; if (P) { if (P->en) pj_dalloc(P->en); pj_dalloc(P); } }ENTRY1(imw_p, en)	double del, sig, s, t, x1, x2, T2, y1, m1, m2, y2;	int i;	if (!(P->en = pj_enfn(P->es))) E_ERROR_0;	if( (i = phi12(P, &del, &sig)) != 0)		E_ERROR(i);	if (P->phi_2 < P->phi_1) { /* make sure P->phi_1 most southerly */		del = P->phi_1;		P->phi_1 = P->phi_2;		P->phi_2 = del;	}	if (pj_param(P->params, "tlon_1").i)		P->lam_1 = pj_param(P->params, "rlon_1").f;	else { /* use predefined based upon latitude */		sig = fabs(sig * RAD_TO_DEG);		if (sig <= 60)		sig = 2.;		else if (sig <= 76) sig = 4.;		else				sig = 8.;		P->lam_1 = sig * DEG_TO_RAD;	}	P->mode = 0;	if (P->phi_1) xy(P, P->phi_1, &x1, &y1, &P->sphi_1, &P->R_1);	else {		P->mode = 1;		y1 = 0.;		x1 = P->lam_1;	}	if (P->phi_2) xy(P, P->phi_2, &x2, &T2, &P->sphi_2, &P->R_2);	else {		P->mode = -1;		T2 = 0.;		x2 = P->lam_1;	}	m1 = pj_mlfn(P->phi_1, P->sphi_1, cos(P->phi_1), P->en);	m2 = pj_mlfn(P->phi_2, P->sphi_2, cos(P->phi_2), P->en);	t = m2 - m1;	s = x2 - x1;	y2 = sqrt(t * t - s * s) + y1;	P->C2 = y2 - T2;	t = 1. / t;	P->P = (m2 * y1 - m1 * y2) * t;	P->Q = (y2 - y1) * t;	P->Pp = (m2 * x1 - m1 * x2) * t;	P->Qp = (x2 - x1) * t;	P->fwd = e_forward;	P->inv = e_inverse;ENDENTRY(P)