Initial revision.

1997-07-07 21:02:36 +00:00
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+/**************************************************************************
+ * polar.h -- routines to deal with polar math and transformations
+ *
+ * Written by Curtis Olson, started June 1997.
+ *
+ * Copyright (C) 1997  Curtis L. Olson  - curt@infoplane.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id$
+ * (Log is kept at end of this file)
+ **************************************************************************/
+
+
+#ifndef POLAR_H
+#define POLAR_H
+
+
+#include "../types.h"
+
+
+/* Convert a geodetic coordinate to a cartesian coordinat on the unit
+ * circle, scaled by the radius of the earth in meters.  Ignores Altitude,
+ * since this is just for translating points around on the surface. */
+struct fgCartesianPoint fgGeodetic2Cartesian(double lon, double lat);
+
+/* Precalculate as much as possible so we can do a batch of transforms
+ * through the same angles, will rotates a cartesian point about the
+ * center of the earth by Theta (longitude axis) and Phi (latitude
+ * axis) */
+
+/* Here are the unoptimized transformation equations 
+
+   x' = cos(Phi) * cos(Theta) * x + cos(Phi) * sin(Theta) * y + 
+	     sin(Phi) * z
+   y' = -sin(Theta) * x + cos(Theta) * y
+   z' = -sin(Phi) * sin(Theta) * y - sin(Phi) * cos(Theta) * x + 
+	     cos(Phi) * z;
+
+ */
+void fgRotateBatchInit(double Theta, double Phi);
+
+/* Rotates a cartesian point about the center of the earth by Theta
+ * (longitude axis) and Phi (latitude axis) */
+struct fgCartesianPoint fgRotateCartesianPoint(struct fgCartesianPoint p);
+
+
+#endif POLAR_H
+
+
+/* $Log$
+/* Revision 1.1  1997/07/07 21:02:37  curt
+/* Initial revision.
+/*
+ */