PolarStereographic.cpp

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#include "PolarStereographic.h"

#include <cmath>
#include <cfloat>
#include <iostream>

#include "Constants.h"
#include "IException.h"
#include "TProjection.h"
#include "Pvl.h"
#include "PvlGroup.h"
#include "PvlKeyword.h"

using namespace std;
namespace Isis {
  PolarStereographic::PolarStereographic(Pvl &label, bool allowDefaults) :
    TProjection::TProjection(label) {
    try {
      // Try to read the mapping group
      PvlGroup &mapGroup = label.findGroup("Mapping", Pvl::Traverse);

      // Compute and write the default center longitude if allowed and
      // necessary
      if ((allowDefaults) && (!mapGroup.hasKeyword("CenterLongitude"))) {
        double lon = (m_minimumLongitude + m_maximumLongitude) / 2.0;
        mapGroup += PvlKeyword("CenterLongitude", toString(lon));
      }

      // Compute and write the default center latitude if allowed and
      // necessary
      if ((allowDefaults) && (!mapGroup.hasKeyword("CenterLatitude"))) {
        double lat = (m_minimumLatitude + m_maximumLatitude) / 2.0;
        if (lat > 0.0) {
          mapGroup += PvlKeyword("CenterLatitude", toString(90.0));
        }
        else {
          mapGroup += PvlKeyword("CenterLatitude", toString(-90.0));
        }
      }

      // Get the center longitude, convert to radians and adjust for longitude
      // direction
      m_centerLongitude = mapGroup["CenterLongitude"];
      m_centerLongitude *= PI / 180.0;
      if (m_longitudeDirection == PositiveWest) m_centerLongitude *= -1.0;

      // Get the center latitude, make sure it is ographic, and convert to
      // radians.
      m_centerLatitude = mapGroup["CenterLatitude"];
      if (m_centerLatitude == 0) {
        QString msg = "Invalid value for keyword [CenterLatitude] in map file.";
        msg += "  CenterLatitude cannot equal 0.0";
        throw IException(IException::User, msg, _FILEINFO_);
      }
      if (IsPlanetocentric()) {
        m_centerLatitude = ToPlanetographic(m_centerLatitude);
      }
      m_centerLatitude *= PI / 180.0;

      // Compute some constants
      m_e4 = e4Compute();
      m_signFactor = 1.0;
      if (m_centerLatitude < 0.0) m_signFactor = -1.0;

      if ((HALFPI - fabs(m_centerLatitude)) > DBL_EPSILON) {
        m_poleFlag = true;  // We are not at a pole
        double phi = m_signFactor * m_centerLatitude;
        double sinphi = sin(phi);
        double cosphi = cos(phi);
        m_m = mCompute(sinphi, cosphi);
        m_t = tCompute(phi, sinphi);
        if (fabs(m_t) < DBL_EPSILON) m_poleFlag = false;
      }
      else {
        m_poleFlag = false;  // Implies we are at a pole
        m_m = 0; 
        m_t = 0;
      }
    }
    catch(IException &e) {
      QString message = "Invalid label group [Mapping]";
      throw IException(e, IException::Unknown, message, _FILEINFO_);
    }
  }
  

  PolarStereographic::~PolarStereographic() {
  }
  

  bool PolarStereographic::operator== (const Projection &proj) {
    if (!Projection::operator==(proj)) return false;
    // dont do the below it is a recusive plunge
    //  if (Projection::operator!=(proj)) return false;
    PolarStereographic *pola = (PolarStereographic *) &proj;
    if (pola->m_centerLongitude != m_centerLongitude) return false;
    if (pola->m_centerLatitude != m_centerLatitude) return false;
    return true;
  }
  

  QString PolarStereographic::Name() const {
    return "PolarStereographic";
  }

  
  QString PolarStereographic::Version() const {
    return "1.0";
  }

  
  double PolarStereographic::TrueScaleLatitude() const {
    return m_centerLatitude * 180.0 / PI;
  }

  
  bool PolarStereographic::SetGround(const double lat, const double lon) {
    // Fix up longitude
    m_longitude = lon;
    double lonRadians = lon * PI / 180.0;
    if (m_longitudeDirection == PositiveWest) lonRadians *= -1.0;

    // Now do latitude ... it must be planetographic
    m_latitude = lat;
    double latRadians = lat;
    if (IsPlanetocentric()) latRadians = ToPlanetographic(latRadians);
    latRadians = latRadians * PI / 180.0;

    // Compute easting and northing
    double lamda = m_signFactor * (lonRadians - m_centerLongitude);
    double phi = m_signFactor * latRadians;
    double sinphi = sin(phi);
    double t = tCompute(phi, sinphi);

    double dist;
    if (m_poleFlag) {
      dist = m_equatorialRadius * m_m * t / m_t;
    }
    else {
      dist = m_equatorialRadius * 2.0 * t / m_e4;
    }

    double x = m_signFactor * dist * sin(lamda);
    double y = -(m_signFactor * dist * cos(lamda));
    SetComputedXY(x, y);

    m_good = true;

    //So we don't project the wrong pole.
    if (qFuzzyCompare(lat * m_signFactor, -90.0))
      m_good = false;

    return m_good;
  }

  
  bool PolarStereographic::SetCoordinate(const double x, const double y) {
    // Save the coordinate
    SetXY(x, y);

    double east = m_signFactor * GetX();
    double north = m_signFactor * GetY();
    double dist = sqrt(east * east + north * north);

    double t;
    if (m_poleFlag) {
      t = dist * m_t / (m_m * m_equatorialRadius); // Snyder eqn (21-40)
    }
    else {
      t = dist * m_e4 / (2.0 * m_equatorialRadius); //Snyder eqn (24-39) 
                                                    //when latitude of true scale is North Polar
    }

    // Compute the latitude
    double phi = phi2Compute(t);
    m_latitude = m_signFactor * phi;

    if (fabs(m_latitude) > HALFPI) {
      QString msg = "X,Y causes latitude to be outside [-90,90] "
                   "in PolarStereographic Class";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }

    // Compute the longitude
    if (dist == 0.0) {
      m_longitude = m_signFactor * m_centerLongitude;
    }
    else {
      m_longitude = m_signFactor * atan2(east, -north) + m_centerLongitude;
    }

    // Cleanup the longitude
    m_longitude *= 180.0 / PI;
    if (m_longitudeDirection == PositiveWest) m_longitude *= -1.0;
    m_longitude = To360Domain(m_longitude);
    if (m_longitudeDomain == 180) m_longitude = To180Domain(m_longitude);

    // Cleanup the latitude
    m_latitude *= 180.0 / PI;
    if (IsPlanetocentric()) m_latitude = ToPlanetocentric(m_latitude);

    m_good = true;
    return m_good;
  }

  
  bool PolarStereographic::XYRange(double &minX, double &maxX,
                                   double &minY, double &maxY) {
    // Check the corners of the lat/lon range
    XYRangeCheck(m_minimumLatitude, m_minimumLongitude);
    XYRangeCheck(m_maximumLatitude, m_minimumLongitude);
    XYRangeCheck(m_minimumLatitude, m_maximumLongitude);
    XYRangeCheck(m_maximumLatitude, m_maximumLongitude);

    // Find the closest longitude >= to the minimum longitude that is offset
    // from the center longitude by a multiple of 90.
    double lon1 = m_centerLongitude * 180.0 / PI;
    if (m_longitudeDirection == PositiveWest) lon1 *= -1.0;
    while(lon1 > m_minimumLongitude) lon1 -= 90.0;
    while(lon1 < m_minimumLongitude) lon1 += 90.0;

    while(lon1 <= m_maximumLongitude) {
      XYRangeCheck(m_minimumLatitude, lon1);
      XYRangeCheck(m_maximumLatitude, lon1);
      lon1 += 90.0;
    }

    // Make sure everything is ordered
    if (m_minimumX >= m_maximumX) return false;
    if (m_minimumY >= m_maximumY) return false;

    // Return X/Y min/maxs
    minX = m_minimumX;
    maxX = m_maximumX;
    minY = m_minimumY;
    maxY = m_maximumY;
    return true;
  }
  

  PvlGroup PolarStereographic::Mapping() {
    PvlGroup mapping = TProjection::Mapping();

    mapping += m_mappingGrp["CenterLatitude"];
    mapping += m_mappingGrp["CenterLongitude"];

    return mapping;
  }

  
  PvlGroup PolarStereographic::MappingLatitudes() {
    PvlGroup mapping = TProjection::MappingLatitudes();

    mapping += m_mappingGrp["CenterLatitude"];

    return mapping;
  }

  
  PvlGroup PolarStereographic::MappingLongitudes() {
    PvlGroup mapping = TProjection::MappingLongitudes();

    mapping += m_mappingGrp["CenterLongitude"];

    return mapping;
  }
}


extern "C" Isis::Projection *PolarStereographicPlugin(Isis::Pvl &lab,
    bool allowDefaults) {
  return new Isis::PolarStereographic(lab, allowDefaults);
}