New

git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@776 4e78687f-474d-0410-85f9-8d5e500ac6b2

1 files changed, 152 insertions, 0 deletions

diff --git a/src/PJ_nsper.c b/src/PJ_nsper.c
new file mode 100644
index 00000000..6b430a84
--- /dev/null
+++ b/src/PJ_nsper.c
@@ -0,0 +1,152 @@
+#ifndef lint
+static const char SCCSID[]="@(#)PJ_nsper.c	4.1	94/02/15	GIE	REL";
+#endif
+#define PROJ_PARMS__ \
+	double	height; \
+	double	sinph0; \
+	double	cosph0; \
+	double	p; \
+	double	rp; \
+	double	pn1; \
+	double	pfact; \
+	double	h; \
+	double	cg; \
+	double	sg; \
+	double	sw; \
+	double	cw; \
+	int		mode; \
+	int		tilt;
+#define PJ_LIB__
+#include	<projects.h>
+PROJ_HEAD(nsper, "Near-sided perspective") "\n\tAzi, Sph\n\th=";
+PROJ_HEAD(tpers, "Tilted perspective") "\n\tAzi, Sph\n\ttilt= azi= h=";
+# define EPS10 1.e-10
+# define N_POLE	0
+# define S_POLE 1
+# define EQUIT	2
+# define OBLIQ	3
+FORWARD(s_forward); /* spheroid */
+	double  coslam, cosphi, sinphi;
+
+	sinphi = sin(lp.phi);
+	cosphi = cos(lp.phi);
+	coslam = cos(lp.lam);
+	switch (P->mode) {
+	case OBLIQ:
+		xy.y = P->sinph0 * sinphi + P->cosph0 * cosphi * coslam;
+		break;
+	case EQUIT:
+		xy.y = cosphi * coslam;
+		break;
+	case S_POLE:
+		xy.y = - sinphi;
+		break;
+	case N_POLE:
+		xy.y = sinphi;
+		break;
+	}
+	if (xy.y < P->rp) F_ERROR;
+	xy.y = P->pn1 / (P->p - xy.y);
+	xy.x = xy.y * cosphi * sin(lp.lam);
+	switch (P->mode) {
+	case OBLIQ:
+		xy.y *= (P->cosph0 * sinphi -
+		   P->sinph0 * cosphi * coslam);
+		break;
+	case EQUIT:
+		xy.y *= sinphi;
+		break;
+	case N_POLE:
+		coslam = - coslam;
+	case S_POLE:
+		xy.y *= cosphi * coslam;
+		break;
+	}
+	if (P->tilt) {
+		double yt, ba;
+
+		yt = xy.y * P->cg + xy.x * P->sg;
+		ba = 1. / (yt * P->sw * P->h + P->cw);
+		xy.x = (xy.x * P->cg - xy.y * P->sg) * P->cw * ba;
+		xy.y = yt * ba;
+	}
+	return (xy);
+}
+INVERSE(s_inverse); /* spheroid */
+	double  rh, cosz, sinz;
+
+	if (P->tilt) {
+		double bm, bq, yt;
+
+		yt = 1./(P->pn1 - xy.y * P->sw);
+		bm = P->pn1 * xy.x * yt;
+		bq = P->pn1 * xy.y * P->cw * yt;
+		xy.x = bm * P->cg + bq * P->sg;
+		xy.y = bq * P->cg - bm * P->sg;
+	}
+	rh = hypot(xy.x, xy.y);
+	if ((sinz = 1. - rh * rh * P->pfact) < 0.) I_ERROR;
+	sinz = (P->p - sqrt(sinz)) / (P->pn1 / rh + rh / P->pn1);
+	cosz = sqrt(1. - sinz * sinz);
+	if (fabs(rh) <= EPS10) {
+		lp.lam = 0.;
+		lp.phi = P->phi0;
+	} else {
+		switch (P->mode) {
+		case OBLIQ:
+			lp.phi = asin(cosz * P->sinph0 + xy.y * sinz * P->cosph0 / rh);
+			xy.y = (cosz - P->sinph0 * sin(lp.phi)) * rh;
+			xy.x *= sinz * P->cosph0;
+			break;
+		case EQUIT:
+			lp.phi = asin(xy.y * sinz / rh);
+			xy.y = cosz * rh;
+			xy.x *= sinz;
+			break;
+		case N_POLE:
+			lp.phi = asin(cosz);
+			xy.y = -xy.y;
+			break;
+		case S_POLE:
+			lp.phi = - asin(cosz);
+			break;
+		}
+		lp.lam = atan2(xy.x, xy.y);
+	}
+	return (lp);
+}
+FREEUP; if (P) pj_dalloc(P); }
+	static PJ *
+setup(PJ *P) {
+	if ((P->height = pj_param(P->params, "dh").f) <= 0.) E_ERROR(-30);
+	if (fabs(fabs(P->phi0) - HALFPI) < EPS10)
+		P->mode = P->phi0 < 0. ? S_POLE : N_POLE;
+	else if (fabs(P->phi0) < EPS10)
+		P->mode = EQUIT;
+	else {
+		P->mode = OBLIQ;
+		P->sinph0 = sin(P->phi0);
+		P->cosph0 = cos(P->phi0);
+	}
+	P->pn1 = P->height / P->a; /* normalize by radius */
+	P->p = 1. + P->pn1;
+	P->rp = 1. / P->p;
+	P->h = 1. / P->pn1;
+	P->pfact = (P->p + 1.) * P->h;
+	P->inv = s_inverse;
+	P->fwd = s_forward;
+	P->es = 0.;
+	return P;
+}
+ENTRY0(nsper)
+	P->tilt = 0;
+ENDENTRY(setup(P))
+ENTRY0(tpers)
+	double omega, gamma;
+
+	omega = pj_param(P->params, "dtilt").f * DEG_TO_RAD;
+	gamma = pj_param(P->params, "dazi").f * DEG_TO_RAD;
+	P->tilt = 1;
+	P->cg = cos(gamma); P->sg = sin(gamma);
+	P->cw = cos(omega); P->sw = sin(omega);
+ENDENTRY(setup(P))