1 files changed, 105 insertions, 0 deletions
diff --git a/src/3rdparty/proj/PJ_gnom.c b/src/3rdparty/proj/PJ_gnom.c
new file mode 100644
index 00000000..11deb86c
--- /dev/null
+++ b/src/3rdparty/proj/PJ_gnom.c
@@ -0,0 +1,105 @@
+#define PROJ_PARMS__ \
+	double	sinph0; \
+	double	cosph0; \
+	int		mode;
+#define PJ_LIB__
+#include	<projects.h>
+PROJ_HEAD(gnom, "Gnomonic") "\n\tAzi, Sph.";
+#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 EQUIT:
+		xy.y = cosphi * coslam;
+		break;
+	case OBLIQ:
+		xy.y = P->sinph0 * sinphi + P->cosph0 * cosphi * coslam;
+		break;
+	case S_POLE:
+		xy.y = - sinphi;
+		break;
+	case N_POLE:
+		xy.y = sinphi;
+		break;
+	}
+	if (xy.y <= EPS10) F_ERROR;
+	xy.x = (xy.y = 1. / xy.y) * cosphi * sin(lp.lam);
+	switch (P->mode) {
+	case EQUIT:
+		xy.y *= sinphi;
+		break;
+	case OBLIQ:
+		xy.y *= P->cosph0 * sinphi - P->sinph0 * cosphi * coslam;
+		break;
+	case N_POLE:
+		coslam = - coslam;
+	case S_POLE:
+		xy.y *= cosphi * coslam;
+		break;
+	}
+	return (xy);
+}
+INVERSE(s_inverse); /* spheroid */
+	double  rh, cosz, sinz;
+
+	rh = hypot(xy.x, xy.y);
+	sinz = sin(lp.phi = atan(rh));
+	cosz = sqrt(1. - sinz * sinz);
+	if (fabs(rh) <= EPS10) {
+		lp.phi = P->phi0;
+		lp.lam = 0.;
+	} else {
+		switch (P->mode) {
+		case OBLIQ:
+			lp.phi = cosz * P->sinph0 + xy.y * sinz * P->cosph0 / rh;
+			if (fabs(lp.phi) >= 1.)
+				lp.phi = lp.phi > 0. ? HALFPI : - HALFPI;
+			else
+				lp.phi = asin(lp.phi);
+			xy.y = (cosz - P->sinph0 * sin(lp.phi)) * rh;
+			xy.x *= sinz * P->cosph0;
+			break;
+		case EQUIT:
+			lp.phi = xy.y * sinz / rh;
+			if (fabs(lp.phi) >= 1.)
+				lp.phi = lp.phi > 0. ? HALFPI : - HALFPI;
+			else
+				lp.phi = asin(lp.phi);
+			xy.y = cosz * rh;
+			xy.x *= sinz;
+			break;
+		case S_POLE:
+			lp.phi -= HALFPI;
+			break;
+		case N_POLE:
+			lp.phi = HALFPI - lp.phi;
+			xy.y = -xy.y;
+			break;
+		}
+		lp.lam = atan2(xy.x, xy.y);
+	}
+	return (lp);
+}
+FREEUP; if (P) pj_dalloc(P); }
+ENTRY0(gnom)
+	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->inv = s_inverse;
+	P->fwd = s_forward;
+	P->es = 0.;
+ENDENTRY(P)