m_geodetic.cc

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/* Copyright (C) 2012
   Patrick Eriksson <Patrick.Eriksson@chalmers.se>
                            
   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, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
   USA. */



/*===========================================================================
  === File description 
  ===========================================================================*/

/*===========================================================================
  === External declarations
  ===========================================================================*/

#include <cmath>
#include <stdexcept>
#include "arts.h"
#include "check_input.h"
#include "geodetic.h"
#include "matpackI.h"
#include "messages.h"


extern const Numeric DEG2RAD;


/*===========================================================================
  === The functions (in alphabetical order)
  ===========================================================================*/

/* Workspace method: Doxygen documentation will be auto-generated */
void refellipsoidForAzimuth( 
         Vector&     refellipsoid,
   const Numeric&    latitude,
   const Numeric&    azimuth,
   const Verbosity& )
{
  if( refellipsoid.nelem() != 2 )
    throw runtime_error( "Input *refellispoid must be a vector of length 2*." );

  if( refellipsoid[1] > 0 )
    {
      const Numeric e2  = refellipsoid[1] * refellipsoid[1];
      const Numeric a   = 1 - e2 * pow( sin( DEG2RAD*latitude ), 2.0 );

      const Numeric rn = 1 / sqrt( a );
      const Numeric rm = ( 1 - e2 ) * ( rn / a );

      const Numeric v = DEG2RAD * azimuth;

      refellipsoid[0] = refellipsoid[0] / ( pow(cos(v),2.0)/rm +
                                            pow(sin(v),2.0)/rn ); 
      refellipsoid[1] = 0;
    }
}



/* Workspace method: Doxygen documentation will be auto-generated */
void refellipsoidOrbitPlane( 
         Vector&     refellipsoid,
   const Numeric&    orbitinc,
   const Verbosity& )
{
  if( refellipsoid.nelem() != 2 )
    throw runtime_error( "Input *refellispoid must be a vector of length 2*." );
  chk_if_in_range( "orbitinc", orbitinc,  0, 180 );    

  // Radius at maximum latitude
  const Numeric rp = refell2r( refellipsoid, orbitinc );

  // New eccentricity
  refellipsoid[1] = sqrt( 1 - pow( rp/refellipsoid[0], 2.0 ) );
}



/* Workspace method: Doxygen documentation will be auto-generated */
void refellipsoidSet(            
         Vector&    refellipsoid,
   const Numeric&   re,
   const Numeric&   e,
   const Verbosity& )
{
  refellipsoid.resize(2);

  refellipsoid[0] = re;
  refellipsoid[1] = e;
}