ossimPolyconicProjection.cpp

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//*******************************************************************
// Copyright (C) 2000 ImageLinks Inc.
//
// License:  See top LICENSE.txt file.
//
// Author:  Garrett Potts
//
// Description:
//
// Calls Geotrans Polyconic  projection code.  
//*******************************************************************
//  $Id: ossimPolyconicProjection.cpp 9094 2006-06-13 19:12:40Z dburken $

#include <math.h>
#include <ossim/projection/ossimPolyconicProjection.h>
#include <ossim/base/ossimKeywordNames.h>

RTTI_DEF1(ossimPolyconicProjection, "ossimPolyconicProjection", ossimMapProjection)
/***************************************************************************/
/*
 *                              DEFINES
 */
#ifndef PI_OVER_2
#  define PI_OVER_2  ( M_PI / 2.0)
#endif
#ifndef TWO_PI
#  define TWO_PI     (2.0 * M_PI)
#endif
#define POLY_COEFF_TIMES_SIN(coeff, x, latit)         (coeff * (sin (x * latit)))
#define POLY_M(c0lat,c1s2lat,c2s4lat,c3s6lat)   (Poly_a*(c0lat - c1s2lat + c2s4lat - c3s6lat)) 
#define FLOAT_EQ(x,v,epsilon)   (((v - epsilon) < x) && (x < (v + epsilon)))
#define FOURTY_ONE (41.0 * M_PI / 180.0)  /* 41 degrees in radians */

#define POLY_NO_ERROR           0x0000
#define POLY_LAT_ERROR          0x0001
#define POLY_LON_ERROR          0x0002
#define POLY_EASTING_ERROR      0x0004
#define POLY_NORTHING_ERROR     0x0008
#define POLY_ORIGIN_LAT_ERROR   0x0010
#define POLY_CENT_MER_ERROR     0x0020
#define POLY_A_ERROR            0x0040
#define POLY_B_ERROR            0x0080
#define POLY_A_LESS_B_ERROR     0x0100
#define POLY_LON_WARNING        0x0200

ossimPolyconicProjection::ossimPolyconicProjection(const ossimEllipsoid& ellipsoid,
                                                       const ossimGpt& origin)
   :ossimMapProjection(ellipsoid, origin)
{
   setDefaults();
   update();
}

ossimPolyconicProjection::ossimPolyconicProjection(const ossimEllipsoid& ellipsoid,
                                                   const ossimGpt& origin,
                                                   double falseEasting,
                                                   double falseNorthing)
   :ossimMapProjection(ellipsoid, origin)
{
   Poly_False_Easting  = falseEasting;
   Poly_False_Northing = falseNorthing;
   Poly_Max_Easting    = 20037509.0;
   Poly_Max_Northing   = 15348215.0;
   Poly_Min_Easting    = -20037509.0;
   Poly_Min_Northing   = -15348215.0;

   update();
}

void ossimPolyconicProjection::update()
{   
   Set_Polyconic_Parameters(theEllipsoid.getA(),
                            theEllipsoid.getFlattening(),
                            theOrigin.latr(),
                            theOrigin.lonr(),
                            Poly_False_Easting,
                            Poly_False_Northing);

   theFalseEastingNorthing.x = Poly_False_Easting;
   theFalseEastingNorthing.y = Poly_False_Northing;

   ossimMapProjection::update();
}

void ossimPolyconicProjection::setFalseEasting(double falseEasting)
{
   Poly_False_Easting = falseEasting;
   
   update();
}

void ossimPolyconicProjection::setFalseNorthing(double falseNorthing)
{
   Poly_False_Northing = falseNorthing;
   
   update();
}

void ossimPolyconicProjection::setDefaults()
{
   Poly_False_Easting  = 0.0;
   Poly_False_Northing = 0.0;
   Poly_Max_Easting    = 20037509.0;
   Poly_Max_Northing   = 15348215.0;
   Poly_Min_Easting    = -20037509.0;
   Poly_Min_Northing   = -15348215.0;
}

void ossimPolyconicProjection::setFalseEastingNorthing(double falseEasting,
                                                      double falseNorthing)
{
   Poly_False_Easting  = falseEasting;
   Poly_False_Northing = falseNorthing;
   
   update();
}

ossimGpt ossimPolyconicProjection::inverse(const ossimDpt &eastingNorthing)const
{
   double lat = 0.0;
   double lon = 0.0;

   Convert_Polyconic_To_Geodetic(eastingNorthing.x,
                                 eastingNorthing.y,
                                 &lat,
                                 &lon);
   
   return ossimGpt(lat*DEG_PER_RAD, lon*DEG_PER_RAD, 0.0, theDatum);  
}

ossimDpt ossimPolyconicProjection::forward(const ossimGpt &latLon)const
{
   double easting  = 0.0;
   double northing = 0.0;
   ossimGpt gpt = latLon;
   
   if (theDatum)
   {
      if (theDatum->code() != latLon.datum()->code())
      {
         gpt.changeDatum(theDatum); // Shift to our datum.
      }
   }

   Convert_Geodetic_To_Polyconic(gpt.latr(),
                                 gpt.lonr(),
                                 &easting,
                                 &northing);
   
   return ossimDpt(easting, northing);
}

bool ossimPolyconicProjection::saveState(ossimKeywordlist& kwl, const char* prefix) const
{
   return ossimMapProjection::saveState(kwl, prefix);
}

bool ossimPolyconicProjection::loadState(const ossimKeywordlist& kwl,
                                         const char* prefix)
{
   bool flag = ossimMapProjection::loadState(kwl, prefix);
   const char* type          = kwl.find(prefix, ossimKeywordNames::TYPE_KW);
   
   setDefaults();

   if(ossimString(type) == STATIC_TYPE_NAME(ossimPolyconicProjection))
   {
      Poly_False_Easting  = theFalseEastingNorthing.x;
      Poly_False_Northing = theFalseEastingNorthing.y;
   }
   
   update();

   return flag;
}

/***************************************************************************/
/*
 *                              FUNCTIONS     
 */


long ossimPolyconicProjection::Set_Polyconic_Parameters(double a,
                                                        double f,
                                                        double Origin_Latitude,
                                                        double Central_Meridian,
                                                        double False_Easting,
                                                        double False_Northing)

{ /* BEGIN Set_Polyconic_Parameters */
/*
 * The function Set_Polyconic_Parameters receives the ellipsoid parameters and
 * Polyconic projection parameters as inputs, and sets the corresponding state
 * variables.  If any errors occur, the error code(s) are returned by the function, 
 * otherwise POLY_NO_ERROR is returned.
 *
 *    a                 : Semi-major axis of ellipsoid, in meters   (input)
 *    f                 : Flattening of ellipsoid                               (input)
 *    Origin_Latitude   : Latitude in radians at which the          (input)
 *                          point scale factor is 1.0
 *    Central_Meridian  : Longitude in radians at the center of     (input)
 *                          the projection
 *    False_Easting     : A coordinate value in meters assigned to the
 *                          central meridian of the projection.     (input)
 *    False_Northing    : A coordinate value in meters assigned to the
 *                          origin latitude of the projection       (input)
 */

  double j, three_es4;
  double lat, sin2lat, sin4lat, sin6lat;
  double temp;
//  double inv_f = 1 / f;
  long Error_Code = POLY_NO_ERROR;

//   if (a <= 0.0)
//   { /* Semi-major axis must be greater than zero */
//     Error_Code |= POLY_A_ERROR;
//   }
//   if ((inv_f < 250) || (inv_f > 350))
//   { /* Inverse flattening must be between 250 and 350 */
//     Error_Code |= POLY_INV_F_ERROR;
//   }
//   if ((Origin_Latitude < -PI_OVER_2) || (Origin_Latitude > PI_OVER_2))
//   { /* origin latitude out of range */
//     Error_Code |= POLY_ORIGIN_LAT_ERROR;
//   }
//   if ((Central_Meridian < -M_PI) || (Central_Meridian > TWO_PI))
//   { /* origin longitude out of range */
//     Error_Code |= POLY_CENT_MER_ERROR;
//   }
  if (!Error_Code)
  { /* no errors */
    Poly_a = a;
    Poly_f = f;
    Poly_Origin_Lat = Origin_Latitude;
//     if (Central_Meridian > M_PI)
//       Central_Meridian -= TWO_PI;
    Poly_Origin_Long = Central_Meridian;
    Poly_False_Northing = False_Northing;
    Poly_False_Easting = False_Easting;
    es2 = 2 * Poly_f - Poly_f * Poly_f;
    es4 = es2 * es2;
    es6 = es4 * es2;

    j = 45.0 * es6 / 1024.0;
    three_es4 = 3.0 * es4;
    c0 = 1.0 - es2 / 4.0 - three_es4 / 64.0 - 5.0 * es6 / 256.0;
    c1 = 3.0 * es2 / 8.0 + three_es4 / 32.0 + j;
    c2 = 15.0 * es4 / 256.0 + j;
    c3 = 35.0 * es6 / 3072.0;

    lat = c0 * Poly_Origin_Lat;
    sin2lat = POLY_COEFF_TIMES_SIN(c1, 2.0, Poly_Origin_Lat);
    sin4lat = POLY_COEFF_TIMES_SIN(c2, 4.0, Poly_Origin_Lat);
    sin6lat = POLY_COEFF_TIMES_SIN(c3, 6.0, Poly_Origin_Lat);
    M0 = POLY_M(lat, sin2lat, sin4lat, sin6lat);

    if (Poly_Origin_Long > 0)
    {
      Convert_Geodetic_To_Polyconic(FOURTY_ONE, Poly_Origin_Long - M_PI, &temp, &Poly_Max_Northing);
      Convert_Geodetic_To_Polyconic(-FOURTY_ONE, Poly_Origin_Long - M_PI, &temp, &Poly_Min_Northing);
      Poly_Max_Easting = 19926189.0;
      Poly_Min_Easting = -20037509.0;
    }
    else if (Poly_Origin_Long < 0)
    {
      Convert_Geodetic_To_Polyconic(FOURTY_ONE, Poly_Origin_Long + M_PI, &temp, &Poly_Max_Northing);
      Convert_Geodetic_To_Polyconic(-FOURTY_ONE, Poly_Origin_Long + M_PI, &temp, &Poly_Min_Northing);
      Poly_Max_Easting = 20037509.0;
      Poly_Min_Easting = -19926189.0;
    }
    else
    {
      Convert_Geodetic_To_Polyconic(FOURTY_ONE, M_PI, &temp, &Poly_Max_Northing);
      Convert_Geodetic_To_Polyconic(-FOURTY_ONE, M_PI, &temp, &Poly_Min_Northing);
      Poly_Max_Easting = 20037509.0;
      Poly_Min_Easting = -20037509.0;
    }

  } /* END OF if(!Error_Code) */
  return (Error_Code);
} /* END OF Set_Polyconic_Parameters */

void ossimPolyconicProjection::Get_Polyconic_Parameters(double *a,
                                                        double *f,
                                                        double *Origin_Latitude,
                                                        double *Central_Meridian,
                                                        double *False_Easting,
                                                        double *False_Northing)const

{ /* BEGIN Get_Polyconic_Parameters */
/*
 * The function Get_Polyconic_Parameters returns the current ellipsoid
 * parameters, and Polyconic projection parameters.
 *
 *    a                 : Semi-major axis of ellipsoid, in meters   (output)
 *    f                 : Flattening of ellipsoid                               (output)
 *    Origin_Latitude   : Latitude in radians at which the          (output)
 *                          point scale factor is 1.0
 *    Central_Meridian  : Longitude in radians at the center of     (output)
 *                          the projection
 *    False_Easting     : A coordinate value in meters assigned to the
 *                          central meridian of the projection.     (output)
 *    False_Northing    : A coordinate value in meters assigned to the
 *                          origin latitude of the projection       (output)
 */

  *a = Poly_a;
  *f = Poly_f;
  *Origin_Latitude = Poly_Origin_Lat;
  *Central_Meridian = Poly_Origin_Long;
  *False_Easting = Poly_False_Easting;
  *False_Northing = Poly_False_Northing;
  
  return;
} /* END OF Get_Polyconic_Parameters */


long ossimPolyconicProjection::Convert_Geodetic_To_Polyconic (double Latitude,
                                                              double Longitude,
                                                              double *Easting,
                                                              double *Northing)const
{ /* BEGIN Convert_Geodetic_To_Polyconic */
/*
 * The function Convert_Geodetic_To_Polyconic converts geodetic (latitude and
 * longitude) coordinates to Polyconic projection (easting and northing)
 * coordinates, according to the current ellipsoid and Polyconic projection
 * parameters.  If any errors occur, the error code(s) are returned by the
 * function, otherwise POLY_NO_ERROR is returned.
 *
 *    Latitude          : Latitude (phi) in radians           (input)
 *    Longitude         : Longitude (lambda) in radians       (input)
 *    Easting           : Easting (X) in meters               (output)
 *    Northing          : Northing (Y) in meters              (output)
 */

  double slat = sin(Latitude);
  double lat, sin2lat, sin4lat, sin6lat;
  double dlam;                      /* Longitude - Central Meridan */
  double NN;
  double NN_OVER_tlat;
  double MM;
  double EE;
  long Error_Code = POLY_NO_ERROR;

//   if ((Latitude < -PI_OVER_2) || (Latitude > PI_OVER_2))
//   { /* Latitude out of range */
//     Error_Code |= POLY_LAT_ERROR;
//   }
//   if ((Longitude < -M_PI) || (Longitude > TWO_PI))
//   { /* Longitude out of range */
//     Error_Code |= POLY_LON_ERROR;
//   }
  if (!Error_Code)
  { /* no errors */
    dlam = Longitude - Poly_Origin_Long;
    if (fabs(dlam) > (M_PI / 2.0))
    { /* Distortion will result if Longitude is more than 90 degrees from the Central Meridian */
      Error_Code |= POLY_LON_WARNING;
    }
//     if (dlam > M_PI)
//     {
//       dlam -= TWO_PI;
//     }
//     if (dlam < -M_PI)
//     {
//       dlam += TWO_PI;
//     }
    if (Latitude == 0.0)
    {
      *Easting = Poly_a * dlam + Poly_False_Easting;
      *Northing = -M0 + Poly_False_Northing;
    }
    else
    {
      NN = Poly_a / sqrt(1.0 - es2 * (slat * slat));
      NN_OVER_tlat = NN  / tan(Latitude);
      lat = c0 * Latitude;
      sin2lat = POLY_COEFF_TIMES_SIN(c1, 2.0, Latitude);
      sin4lat = POLY_COEFF_TIMES_SIN(c2, 4.0, Latitude);
      sin6lat = POLY_COEFF_TIMES_SIN(c3, 6.0, Latitude);
      MM = POLY_M(lat, sin2lat, sin4lat, sin6lat);
      EE = dlam * slat;
      *Easting = NN_OVER_tlat * sin(EE) + Poly_False_Easting;
      *Northing = MM - M0 + NN_OVER_tlat * (1.0 - cos(EE)) +
                  Poly_False_Northing;
    }
  }
  return (Error_Code);
} /* END OF Convert_Geodetic_To_Polyconic */


long ossimPolyconicProjection::Convert_Polyconic_To_Geodetic(double Easting,
                                                             double Northing,
                                                             double *Latitude,
                                                             double *Longitude)const
{ /* BEGIN Convert_Polyconic_To_Geodetic */
/*
 * The function Convert_Polyconic_To_Geodetic converts Polyconic projection
 * (easting and northing) coordinates to geodetic (latitude and longitude)
 * coordinates, according to the current ellipsoid and Polyconic projection
 * coordinates.  If any errors occur, the error code(s) are returned by the
 * function, otherwise POLY_NO_ERROR is returned.
 *
 *    Easting           : Easting (X) in meters                  (input)
 *    Northing          : Northing (Y) in meters                 (input)
 *    Latitude          : Latitude (phi) in radians              (output)
 *    Longitude         : Longitude (lambda) in radians          (output)
 */

  double dx;     /* Delta easting - Difference in easting (easting-FE)      */
  double dy;     /* Delta northing - Difference in northing (northing-FN)   */
  double dx_OVER_Poly_a;
  double AA;
  double BB;
  double CC = 0.0;
  double PHIn, Delta_PHI = 1.0;
  double sin_PHIn;
  double PHI, sin2PHI,sin4PHI, sin6PHI;
  double Mn, Mn_prime, Ma;
  double AA_Ma;
  double Ma2_PLUS_BB;
  double AA_MINUS_Ma;
  double tolerance = 1.0e-12;        /* approximately 1/1000th of
                               an arc second or 1/10th meter */
  long Error_Code = POLY_NO_ERROR;

//   if ((Easting < (Poly_False_Easting + Poly_Min_Easting))
//       || (Easting > (Poly_False_Easting + Poly_Max_Easting)))
//   { /* Easting out of range */
//     Error_Code |= POLY_EASTING_ERROR;
//   }
//   if ((Northing < (Poly_False_Northing + Poly_Min_Northing))
//       || (Northing > (Poly_False_Northing + Poly_Max_Northing)))
//   { /* Northing out of range */
//     Error_Code |= POLY_NORTHING_ERROR;
//   }
  if (!Error_Code)
  { /* no errors */
    dy = Northing - Poly_False_Northing;
    dx = Easting - Poly_False_Easting;
    dx_OVER_Poly_a = dx / Poly_a;
    if (FLOAT_EQ(dy,-M0,1))
    {
      *Latitude = 0.0;
      *Longitude = dx_OVER_Poly_a + Poly_Origin_Long;
    }
    else
    {
      AA = (M0 + dy) / Poly_a;
      BB = dx_OVER_Poly_a * dx_OVER_Poly_a + (AA * AA);
      PHIn = AA;

      while (fabs(Delta_PHI) > tolerance)
      {
        sin_PHIn = sin(PHIn);
        CC = sqrt(1.0 - es2 * sin_PHIn * sin_PHIn) * tan(PHIn);
        PHI = c0 * PHIn;
        sin2PHI = POLY_COEFF_TIMES_SIN(c1, 2.0, PHIn);
        sin4PHI = POLY_COEFF_TIMES_SIN(c2, 4.0, PHIn);
        sin6PHI = POLY_COEFF_TIMES_SIN(c3, 6.0, PHIn);
        Mn = POLY_M(PHI, sin2PHI, sin4PHI, sin6PHI);
        Mn_prime = c0 - 2.0 * c1 * cos(2.0 * PHIn) + 4.0 * c2 * cos(4.0 * PHIn) - 
                   6.0 * c3 * cos(6.0 * PHIn);  
        Ma = Mn / Poly_a;
        AA_Ma = AA * Ma;
        Ma2_PLUS_BB = Ma * Ma + BB;
        AA_MINUS_Ma = AA - Ma;
        Delta_PHI = (AA_Ma * CC + AA_MINUS_Ma - 0.5 * (Ma2_PLUS_BB) * CC) /
                    (es2 * sin2PHI * (Ma2_PLUS_BB - 2.0 * AA_Ma) /
                     4.0 * CC + (AA_MINUS_Ma) * (CC * Mn_prime - 2.0 / sin2PHI) - Mn_prime);
        PHIn -= Delta_PHI;
      }
      *Latitude = PHIn;

//       if (*Latitude > PI_OVER_2)  /* force distorted values to 90, -90 degrees */
//         *Latitude = PI_OVER_2;
//       else if (*Latitude < -PI_OVER_2)
//         *Latitude = -PI_OVER_2;

      if (FLOAT_EQ(fabs(*Latitude),PI_OVER_2,.00001) || (*Latitude == 0))
        *Longitude = Poly_Origin_Long;

      else
      {
        *Longitude = (asin(dx_OVER_Poly_a * CC)) / sin(*Latitude) +
                     Poly_Origin_Long;
      }
    }
//     if (*Longitude > M_PI)
//       *Longitude -= TWO_PI;
//     if (*Longitude < -M_PI)
//       *Longitude += TWO_PI;

//     if (*Longitude > M_PI)  /* force distorted values to 180, -180 degrees */
//       *Longitude = M_PI;
//     else if (*Longitude < -M_PI)
//       *Longitude = -M_PI;

  }
  return (Error_Code);
} /* END OF Convert_Polyconic_To_Geodetic */