text: /******************************************************************************
   * $Id$
   *
   * Project:  X-Plane aeronautical data reader
   * Purpose:  Definition of geo-computation functions
   * Author:   Even Rouault, even dot rouault at spatialys.com
   *
   ******************************************************************************
   * Copyright (c) 2008, Even Rouault <even dot rouault at spatialys.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   ****************************************************************************/
  
  #ifndef OGR_GEO_UTILS_H_INCLUDED
  #define OGR_GEO_UTILS_H_INCLUDED
  
  /** The following functions provide computations based on great-circle/
   * orthodromic path, on a sphere with a radius of ~6366707 m.
   * The computations are not necessarily implemented in a very accurate/
   * stable way, and shouldn't be used for points that are too close (less than
   * one meter).
   * They are good enough for example to compute the coordinates of the polygon
   * for an airport runway, from its extreme points, track and length.
   */
  
  double OGR_GreatCircle_Distance(double dfLatA_deg, double dfLonA_deg,
                                  double dfLatB_deg, double dfLonB_deg);
  
  double OGR_GreatCircle_InitialHeading(double dfLatA_deg, double dfLonA_deg,
                                        double dfLatB_deg, double dfLonB_deg);
  
  /* such as ExtendPosition(A, Distance(A,B), InitialHeading(A,B)) ~= B */
  int OGR_GreatCircle_ExtendPosition(double dfLatA_deg, double dfLonA_deg,
                                     double dfDistance, double dfHeadingInA,
                                     double* pdfLatB_deg, double* pdfLonB_deg);
  
  #endif /* ndef OGR_GEO_UTILS_H_INCLUDED */
  