ProcessExportPds4.cpp

#include "ProcessExportPds4.h"

#include <cmath>
#include <iostream>
#include <sstream>

#include <QDomDocument>
#include <QMap>
#include <QRegularExpression>
#include <QString>

#include "Application.h"
#include "FileName.h"
#include "IException.h"
#include "Projection.h"
#include "ProjectionFactory.h"
#include "Pvl.h"
#include "PvlToXmlTranslationManager.h"

using namespace std;

namespace Isis {


  ProcessExportPds4::ProcessExportPds4() {

    m_lid = "";
    m_versionId = "";
    m_title = "";

    m_imageType = StandardImage;

    qSetGlobalQHashSeed(1031); // hash seed to force consistent output

    m_domDoc = new QDomDocument("");

    // base xml file 
    // <?xml version="1.0" encoding="UTF-8"?>
    QString xmlVersion = "version=\"1.0\" encoding=\"utf-8\"";
    QDomProcessingInstruction xmlHeader =
        m_domDoc->createProcessingInstruction("xml", xmlVersion);
    m_domDoc->appendChild(xmlHeader);

    // base pds4 schema location
    m_schemaLocation = "http://pds.nasa.gov/pds4/pds/v1 http://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1B00.xsd"; 

    QString xmlModel;
    xmlModel += "href=\"http://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1B00.sch\" ";
    xmlModel += "schematypens=\"http://purl.oclc.org/dsdl/schematron\"";
    QDomProcessingInstruction header =
        m_domDoc->createProcessingInstruction("xml-model", xmlModel);
    m_domDoc->appendChild(header);

  }


  ProcessExportPds4::~ProcessExportPds4() {
    delete m_domDoc;
    m_domDoc = NULL;
  }


  QDomDocument &ProcessExportPds4::StandardPds4Label() {
    CreateImageLabel();
    translateUnits(*m_domDoc);
    return *m_domDoc;
  }


  void ProcessExportPds4::setImageType(ImageType imageType) {
    m_imageType = imageType;
  }


  void ProcessExportPds4::CreateImageLabel() {
    if (InputCubes.size() == 0) {
      QString msg("Must set an input cube before creating a PDS4 label.");
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    if (m_domDoc->documentElement().isNull()) {
      QDomElement root = m_domDoc->createElement("Product_Observational");
      root.setAttribute("xmlns", "http://pds.nasa.gov/pds4/pds/v1");
      root.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance");
      root.setAttribute("xsi:schemaLocation",
                        "http://pds.nasa.gov/pds4/pds/v1 http://pds.nasa.gov/pds4/pds/v1");
      m_domDoc->appendChild(root);
    }

    try {
      // <Product_Observational>
      //   <Identification_Area>
      identificationArea();
    }
    catch (IException &e) {
      QString msg = "Unable to translate and export identification information.";
      throw IException(e, IException::Programmer, msg, _FILEINFO_);
    }
    try {
      // <Product_Observational>
      //   <Observation_Area>
      standardInstrument();
    }
    catch (IException &e) {
      QString msg = "Unable to translate and export instrument information.";
      throw IException(e, IException::Programmer, msg, _FILEINFO_);
    }
    try {
      // <Product_Observational>
      //   <Observation_Area>
      //     <Discipline_Area>
      //       <disp:Display_Settings>
      displaySettings();
    }
    catch (IException &e) {
      QString msg = "Unable to translate and export display settings.";
      throw IException(e, IException::Programmer, msg, _FILEINFO_);
    }

    try {
      // <Product_Observational>
      //   <Observation_Area>
      //     <Discipline_Area>
      //       <sp:Spectral_Characteristics> OR <img:Imaging>
      standardBandBin();
    } 
    catch (IException &e) {
      QString msg = "Unable to translate and export spectral information.";
      throw IException(e, IException::Programmer, msg, _FILEINFO_);
    }

    try { 
      // <Product_Observational>
      //   <Observation_Area>
      //     <Discipline_Area>
      //       <card:Cartography>
      StandardAllMapping();
    }
    catch (IException &e) {
      QString msg = "Unable to translate and export mapping group.";
      throw IException(e, IException::Programmer, msg, _FILEINFO_);
    }
    try {
      // <Product_Observational>
      //   <File_Area_Observational>
      fileAreaObservational();
    }
    catch (IException &e) {
      QString msg = "Unable to translate and export standard image information.";
      throw IException(e, IException::Programmer, msg, _FILEINFO_);
    }
  }


  void ProcessExportPds4::standardInstrument() {
    Pvl *inputLabel = InputCubes[0]->label();
    FileName translationFileName;

    if (inputLabel->findObject("IsisCube").hasGroup("Instrument")) {
      
      // Translate the Instrument group
      translationFileName = "$base/translations/pds4ExportInstrument.trn";
      PvlToXmlTranslationManager instXlator(*inputLabel, translationFileName.expanded());
      instXlator.Auto(*m_domDoc);
      
      // If instrument and spacecraft values were translated, create the combined name
      QDomElement obsAreaNode = m_domDoc->documentElement().firstChildElement("Observation_Area");
      
      if ( !obsAreaNode.isNull() ) {
      
        // fix start/stop times, if needed
        QDomElement timeNode = obsAreaNode.firstChildElement("Time_Coordinates");
        if (!timeNode.isNull()) {
          QDomElement startTime = timeNode.firstChildElement("start_date_time");
          if (startTime.text() == "") {
            startTime.setAttribute("xsi:nil", "true");
          }
          else {
            QString timeValue = startTime.text();
            PvlToXmlTranslationManager::resetElementValue(startTime, timeValue + "Z"); 
          }
          QDomElement stopTime  = timeNode.firstChildElement("stop_date_time"); 
          if (stopTime.text() == "") {
            stopTime.setAttribute("xsi:nil", "true");
          }
          else {
            QString timeValue = stopTime.text();
            PvlToXmlTranslationManager::resetElementValue(stopTime, timeValue + "Z");
          }
        }
      
        QDomElement obsSysNode = obsAreaNode.firstChildElement("Observing_System");
        if ( !obsSysNode.isNull() ) {
          QString instrumentName;
          QString spacecraftName;
          QDomElement obsSysCompNode = obsSysNode.firstChildElement("Observing_System_Component");
          while ( !obsSysCompNode.isNull()) {
            QDomElement compTypeNode = obsSysCompNode.firstChildElement("type");
            if ( compTypeNode.text().compare("Spacecraft") == 0 ) {
              QString componentName = obsSysCompNode.firstChildElement("name").text();
              if (QString::compare(componentName, "TBD", Qt::CaseInsensitive) != 0) {
                spacecraftName = componentName; 
              }
            }
            else if ( compTypeNode.text().compare("Instrument") == 0 ) {
              QString componentName = obsSysCompNode.firstChildElement("name").text();
              if (QString::compare(componentName, "TBD", Qt::CaseInsensitive) != 0) {
                instrumentName = componentName;
              }
            }
            obsSysCompNode = obsSysCompNode.nextSiblingElement("Observing_System_Component");
          }
          QDomElement combinedNode = m_domDoc->createElement("name");
          QString combinedValue = "TBD";
          if ( !instrumentName.isEmpty() && !spacecraftName.isEmpty() ) {
            combinedValue = spacecraftName + " " + instrumentName;
          }
          combinedNode.appendChild( m_domDoc->createTextNode(combinedValue) );
          obsSysNode.insertBefore( combinedNode, obsSysNode.firstChild() );
        }
      }
      
      // Translate the Target name
      translationFileName = "$base/translations/pds4ExportTargetFromInstrument.trn"; 
      PvlToXmlTranslationManager targXlator(*inputLabel, translationFileName.expanded());
      targXlator.Auto(*m_domDoc);

      // Move target to just below Observing_System. 
      QDomElement targetIdNode = obsAreaNode.firstChildElement("Target_Identification");
      obsAreaNode.insertAfter(targetIdNode, obsAreaNode.firstChildElement("Observing_System"));
    }
    else if (inputLabel->findObject("IsisCube").hasGroup("Mapping")) {

      translationFileName = "$base/translations/pds4ExportTargetFromMapping.trn"; 
      PvlToXmlTranslationManager targXlator(*inputLabel, translationFileName.expanded());
      targXlator.Auto(*m_domDoc);
    }
    else {
      throw IException(IException::Unknown, "Unable to find a target in input cube.", _FILEINFO_);
    }
  }


  void ProcessExportPds4::reorder() {
      QDomElement obsAreaNode = m_domDoc->documentElement().firstChildElement("Observation_Area");
      if ( !obsAreaNode.isNull() ) {

        // fix times
        QDomElement timeNode = obsAreaNode.firstChildElement("Time_Coordinates");
        if (!timeNode.isNull()) {
          QDomElement startTime = timeNode.firstChildElement("start_date_time");
          if (startTime.text() == "") {
            startTime.setAttribute("xsi:nil", "true");
          }
          else {
            QString timeValue = startTime.text();
            if (!timeValue.contains("Z")) {
              PvlToXmlTranslationManager::resetElementValue(startTime, timeValue + "Z"); 
            }
          }

          QDomElement stopTime  = timeNode.firstChildElement("stop_date_time"); 
          if (stopTime.text() == "") {
            stopTime.setAttribute("xsi:nil", "true");
          }
          else {
            QString timeValue = stopTime.text();
            if (!timeValue.contains("Z")) {
              PvlToXmlTranslationManager::resetElementValue(stopTime, timeValue + "Z"); 
            }
          }
          QStringList xmlPath;
          xmlPath << "Product_Observational"
            << "Observation_Area"
            << "Discipline_Area"
            << "geom:Geometry"
            << "geom:Geometry_Orbiter"
            << "geom:geometry_reference_time_utc";

          QDomElement baseElement = m_domDoc->documentElement();
          QDomElement geomRefTime = getElement(xmlPath, baseElement);
          if (geomRefTime.text() == "") {
            geomRefTime.setAttribute("xsi:nil", "true");
          }
          else {
            QString timeValue = geomRefTime.text();
            PvlToXmlTranslationManager::resetElementValue(geomRefTime, timeValue + "Z");
          }
        xmlPath.clear();
          xmlPath << "Product_Observational"
            << "Observation_Area"
            << "Discipline_Area"
            << "geom:Geometry"
            << "geom:Image_Display_Geometry"
            << "geom:Object_Orientation_North_East"
            << "geom:east_azimuth";
          QDomElement eastAzimuth = getElement(xmlPath, baseElement);
          if (eastAzimuth.text() != "") {
            PvlToXmlTranslationManager::resetElementValue(eastAzimuth, eastAzimuth.text(), "deg");
          }
        }

        QDomElement investigationAreaNode = obsAreaNode.firstChildElement("Investigation_Area");
        obsAreaNode.insertAfter(investigationAreaNode, obsAreaNode.firstChildElement("Time_Coordinates"));

        QDomElement obsSystemNode = obsAreaNode.firstChildElement("Observing_System");
        obsAreaNode.insertAfter(obsSystemNode, obsAreaNode.firstChildElement("Investigation_Area"));

        QDomElement targetIdNode = obsAreaNode.firstChildElement("Target_Identification");
        obsAreaNode.insertAfter(targetIdNode, obsAreaNode.firstChildElement("Observing_System"));

        QDomElement missionAreaNode = obsAreaNode.firstChildElement("Mission_Area");
        obsAreaNode.insertAfter(missionAreaNode, obsAreaNode.firstChildElement("Target_Identification"));

        QDomElement disciplineAreaNode = obsAreaNode.firstChildElement("Discipline_Area");
        obsAreaNode.insertAfter(disciplineAreaNode, obsAreaNode.firstChildElement("Mission_Area"));
      }

      QDomElement identificationAreaNode = m_domDoc->documentElement().firstChildElement("Identification_Area");
      if ( !identificationAreaNode.isNull() ) {
        QDomElement aliasListNode = identificationAreaNode.firstChildElement("Alias_List");
        identificationAreaNode.insertAfter(aliasListNode, identificationAreaNode.firstChildElement("product_class"));
      }

      QDomElement fileAreaObservationalNode = m_domDoc->documentElement().firstChildElement("File_Area_Observational");
      QDomElement array2DImageNode = fileAreaObservationalNode.firstChildElement("Array_2D_Image");
      if ( !array2DImageNode.isNull() ) {
        QDomElement descriptionNode = array2DImageNode.firstChildElement("description");
        array2DImageNode.insertAfter(descriptionNode, array2DImageNode.firstChildElement("axis_index_order"));
      }
  }

  void ProcessExportPds4::setLogicalId(QString lid) {
    m_lid = lid.toLower();
  }


   void ProcessExportPds4::setVersionId(QString versionId) {
    m_versionId = versionId;
  }


   void ProcessExportPds4::setTitle(QString title) {
    m_title = title;
  }


  void ProcessExportPds4::setSchemaLocation(QString schema) {
    m_schemaLocation = schema;
  }


  void ProcessExportPds4::identificationArea() {
    Pvl *inputLabel = InputCubes[0]->label(); 
    FileName translationFileName;
    translationFileName = "$base/translations/pds4ExportIdentificationArea.trn";
    PvlToXmlTranslationManager xlator(*inputLabel, translationFileName.expanded());
    xlator.Auto(*m_domDoc);

    if (m_lid.isEmpty()) {
      m_lid = "urn:nasa:pds:TBD:TBD:TBD";
    }

    QDomElement identificationElement;
    QStringList identificationPath;
    identificationPath.append("Product_Observational");
    identificationPath.append("Identification_Area");
    try {
      identificationElement = getElement(identificationPath);
      if( identificationElement.isNull() ) {
        throw IException(IException::Unknown, "", _FILEINFO_);
      }
    }
    catch(IException &e) {
      QString msg = "Could not find Identification_Area element "
                    "to add modification history under.";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }

    QDomElement lidElement = identificationElement.firstChildElement("logical_identifier");
    PvlToXmlTranslationManager::resetElementValue(lidElement, m_lid);

    if (m_versionId != "") {
      QDomElement versionElement = identificationElement.firstChildElement("version_id"); 
      PvlToXmlTranslationManager::resetElementValue(versionElement, m_versionId);
    }

    if (m_title != "") {
      QDomElement titleElement = identificationElement.firstChildElement("title"); 
      PvlToXmlTranslationManager::resetElementValue(titleElement, m_title);
    }

    // Get export history and add <Modification_History> element.
    // These regular expressions match the pipe followed by the date from
    // the Application::Version() return value.
    QRegularExpression versionRegex(" \\| \\d{4}\\-\\d{2}\\-\\d{2}");
    QString historyDescription = "Created PDS4 output product from ISIS cube with the "
                                 + FileName(Application::Name()).baseName()
                                 + " application from ISIS version "
                                 + Application::Version().remove(versionRegex) + ".";
    // This regular expression matches the time from the Application::DateTime return value.
    QRegularExpression dateRegex("T\\d{2}:\\d{2}:\\d{2}");
    QString historyDate = Application::DateTime().remove(dateRegex);
    addHistory(historyDescription, historyDate);
  }

  
  void ProcessExportPds4::displaySettings() {
    // Add header info
    addSchema("PDS4_DISP_1B00.sch", 
              "PDS4_DISP_1B00.xsd",
              "xmlns:disp", 
              "http://pds.nasa.gov/pds4/disp/v1"); 

    Pvl *inputLabel = InputCubes[0]->label(); 
    FileName translationFileName;
    translationFileName = "$base/translations/pds4ExportDisplaySettings.trn";
    PvlToXmlTranslationManager xlator(*inputLabel, translationFileName.expanded());
    xlator.Auto(*m_domDoc);
  }

  
  void ProcessExportPds4::standardBandBin() {
    Pvl *inputLabel = InputCubes[0]->label(); 
    if ( !inputLabel->findObject("IsisCube").hasGroup("BandBin") ) return;
    // Add header info
    addSchema("PDS4_IMG_1A10_1510.sch", 
              "PDS4_IMG_1A10_1510.xsd",
              "xmlns:img", 
              "http://pds.nasa.gov/pds4/img/v1"); 
    
    // Get the input Isis cube label and find the BandBin group if it has one
    if (m_imageType == StandardImage) {
      translateBandBinImage(*inputLabel);
    }
    else {
      // Add header info
      addSchema("PDS4_SP_1100.sch", 
                "PDS4_SP_1100.xsd",
                "xmlns:sp", 
                "http://pds.nasa.gov/pds4/sp/v1");
      if (m_imageType == UniformlySampledSpectrum) {
        translateBandBinSpectrumUniform(*inputLabel);
      }
      else if (m_imageType == BinSetSpectrum) {
        translateBandBinSpectrumBinSet(*inputLabel);
      }
    }
  }


  void ProcessExportPds4::translateBandBinImage(Pvl &inputLabel) {
    QString translationFile = "$base/translations/";
    translationFile += "pds4ExportBandBinImage.trn";
    FileName translationFileName(translationFile);
    PvlToXmlTranslationManager xlator(inputLabel, translationFileName.expanded());
    xlator.Auto(*m_domDoc);
  }


  void ProcessExportPds4::translateBandBinSpectrumUniform(Pvl &inputLabel) {
    QString translationFile = "$base/translations/";
    translationFile += "pds4ExportBandBinSpectrumUniform.trn";
    FileName translationFileName(translationFile);
    PvlToXmlTranslationManager xlator(inputLabel, translationFileName.expanded());
    xlator.Auto(*m_domDoc);

    PvlGroup bandBinGroup = inputLabel.findObject("IsisCube").findGroup("BandBin");
    // fix multi-valued bandbin info
    QStringList xmlPath;
    xmlPath << "Product_Observational"
            << "Observation_Area"
            << "Discipline_Area"
            << "sp:Spectral_Characteristics";
    QDomElement baseElement = m_domDoc->documentElement();
    QDomElement spectralCharElement = getElement(xmlPath, baseElement);

    // Axis_Bin_Set for variable bin widths
    // required - bin_sequence_number, center_value, bin_width
    // optional - detector_number, grating_position, original_bin_number, scaling_factor, value_offset, Filter
    // ... see schema for more...
    PvlKeyword center;
    if (bandBinGroup.hasKeyword("Center")) {
      center = bandBinGroup["Center"];
    }
    else if (bandBinGroup.hasKeyword("FilterCenter")) {
      center = bandBinGroup["FilterCenter"];
    }
    else {
      QString msg = "Unable to translate BandBin info for BinSetSpectrum. "
                    "Translation for PDS4 required value [center_value] not found.";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    PvlKeyword width;
    if (bandBinGroup.hasKeyword("Width")) {
      width = bandBinGroup["Width"];
    }
    else if (bandBinGroup.hasKeyword("FilterWidth")) {
      width = bandBinGroup["FilterWidth"];
    }
    else {
      QString msg = "Unable to translate BandBin info for BinSetSpectrum. "
                    "Translation for PDS4 required value [bin_width] not found.";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }

    QString units = center.unit();

    if (!width.unit().isEmpty() ) {
      if (units.isEmpty()) {
        units = width.unit();
      }
      if (units.compare(width.unit(), Qt::CaseInsensitive) != 0) {
        QString msg = "Unable to translate BandBin info for BinSetSpectrum. "
                      "Unknown or unmatching units for [center_value] and [bin_width].";
        throw IException(IException::Programmer, msg, _FILEINFO_);
      }
    }

    PvlKeyword originalBand;
    if (bandBinGroup.hasKeyword("OriginalBand")) {
      originalBand = bandBinGroup["OriginalBand"];
    }
    PvlKeyword name;
    if (bandBinGroup.hasKeyword("Name")) {
      name = bandBinGroup["Name"];
    }
    else if (bandBinGroup.hasKeyword("FilterName")) {
      name = bandBinGroup["FilterName"];
    }
    else if (bandBinGroup.hasKeyword("FilterId")) {
      name = bandBinGroup["FilterId"];
    }
    PvlKeyword number;
    if (bandBinGroup.hasKeyword("Number")) {
      number = bandBinGroup["Number"];
    }
    else if (bandBinGroup.hasKeyword("FilterNumber")) {
      number = bandBinGroup["FilterNumber"];
    }

    QDomElement axisBinSetElement = spectralCharElement.firstChildElement("sp:Axis_Bin_Set");
    if (axisBinSetElement.isNull()) {
      axisBinSetElement = m_domDoc->createElement("sp:Axis_Bin_Set");
      spectralCharElement.appendChild(axisBinSetElement);
    }
    int bands = (int)inputLabel.findObject("IsisCube")
                                .findObject("Core")
                                .findGroup("Dimensions")
                                .findKeyword("Bands");

    for (int i = 0; i < bands; i++) {

      QDomElement bin = m_domDoc->createElement("sp:Bin");
      axisBinSetElement.appendChild(bin);

      QDomElement binSequenceNumber = m_domDoc->createElement("sp:bin_sequence_number");
      PvlToXmlTranslationManager::setElementValue(binSequenceNumber, toString(i+1));
      bin.appendChild(binSequenceNumber);


      QDomElement centerValue = m_domDoc->createElement("sp:center_value");
      PvlToXmlTranslationManager::setElementValue(centerValue, center[i], units);
      bin.appendChild(centerValue);

      QDomElement binWidth = m_domDoc->createElement("sp:bin_width");
      if (width.size() == bands) {
        PvlToXmlTranslationManager::setElementValue(binWidth, width[i] , units);
      }
      else {
        PvlToXmlTranslationManager::setElementValue(binWidth, width[0] , units);
      }
      bin.appendChild(binWidth);

      QDomElement originalBinNumber = m_domDoc->createElement("sp:original_bin_number");
      if (originalBand.size() > 0) {
        PvlToXmlTranslationManager::setElementValue(originalBinNumber, originalBand[i]);
        bin.appendChild(originalBinNumber);
      }

      if (name.size() > 0 || number.size() > 0) {
        QDomElement filter = m_domDoc->createElement("sp:Filter");
        bin.appendChild(filter);
        if (name.size() > 0) {
          QDomElement filterName = m_domDoc->createElement("sp:filter_name");
          PvlToXmlTranslationManager::setElementValue(filterName, name[i]);
          filter.appendChild(filterName);
        }
        if (number.size() > 0) {
          QDomElement filterNumber= m_domDoc->createElement("sp:filter_number");
          PvlToXmlTranslationManager::setElementValue(filterNumber, number[i]);
          filter.appendChild(filterNumber);
        }
      }
    }
    
  }


  void ProcessExportPds4::translateBandBinSpectrumBinSet(Pvl &inputLabel) {
    QString translationFile = "$base/translations/";
    translationFile += "pds4ExportBandBinSpectrumBinSet.trn";
    FileName translationFileName(translationFile);
    PvlToXmlTranslationManager xlator(inputLabel, translationFileName.expanded());
    xlator.Auto(*m_domDoc);

    PvlGroup bandBinGroup = inputLabel.findObject("IsisCube").findGroup("BandBin");
    // fix multi-valued bandbin info
    QStringList xmlPath;
    xmlPath << "Product_Observational"
            << "Observation_Area"
            << "Discipline_Area"
            << "sp:Spectral_Characteristics";
    QDomElement baseElement = m_domDoc->documentElement();
    QDomElement spectralCharElement = getElement(xmlPath, baseElement);

    // Axis_Uniformly_Sampled
    // required - sampling_parameter_type (frequency, wavelength, wavenumber)
    //            sampling_interval (units Hz, Angstrom, cm**-1, respectively)
    //            bin_width  (units Hz, Angstrom, cm**-1, respectively)
    //            first_center_value  (units Hz, Angstrom, cm**-1, respectively)
    //            last_center_value  (units Hz, Angstrom, cm**-1, respectively) 
    //            Local_Internal_Reference 
    //            Local_Internal_Reference:local_reference_type = spectral_characteristics_to_array_axis
    //            Local_Internal_Reference:local_identifier_reference, 
    //                1. At least one Axis_Array:axis_name must match the 
    //                   value of the local_identifier_reference in the 
    //                   Axis_Uniformly_Sampled.
    //                   Set Axis_Uniformly_Sampled:local_identifier_reference = Axis_Array:axis_name = Band
    //                2. At least one Array_3D_Spectrum:local_identifier must match 
    //                   the value of the local_identifier_reference in the
    //                   Spectral_Characteristics.
    //                   Set Spectral_Characteristics:local_identifier_reference = Array_3D_Spectrum:local_identifier = Spectral_Array_Object
    //            Local_Internal_Reference:local_reference_type = spectral_characteristics_to_array_axis
    PvlKeyword center("Center");
    if (bandBinGroup.hasKeyword("FilterCenter")) {
      center = bandBinGroup["FilterCenter"];
    }
    else if (bandBinGroup.hasKeyword("Center")) {
      center = bandBinGroup["Center"];
    }
    else {
      QString msg = "Unable to translate BandBin info for UniformlySpacedSpectrum. "
                    "Translation for PDS4 required value [last_center_value] not found.";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    QString lastCenter = center[center.size() - 1];

    QDomElement axisBinSetElement = spectralCharElement.firstChildElement("sp:Axis_Uniformly_Sampled");
    if (axisBinSetElement.isNull()) {
      axisBinSetElement = m_domDoc->createElement("sp:Axis_Uniformly_Sampled");
      spectralCharElement.appendChild(axisBinSetElement);
    }

    QDomElement lastCenterElement = m_domDoc->createElement("sp:last_center_value");
    PvlToXmlTranslationManager::setElementValue(lastCenterElement, lastCenter);
    spectralCharElement.appendChild(lastCenterElement);
    
  }

  void ProcessExportPds4::setPixelDescription(QString description) {
    m_pixelDescription = description;
  }

  void ProcessExportPds4::fileAreaObservational() {
    Pvl *inputLabel = InputCubes[0]->label(); 
    QString imageObject = "";

    QString translationFile = "$base/translations/pds4Export";
    if (m_imageType == StandardImage) {
      int bands = (int)inputLabel->findObject("IsisCube")
                                  .findObject("Core")
                                  .findGroup("Dimensions")
                                  .findKeyword("Bands");
      if (bands > 1) {
        imageObject = "Array_3D_Image";
      }
      else {
        imageObject = "Array_2D_Image";
      }
      translationFile += QString(imageObject).remove('_');
    }
    else {
      imageObject = "Array_3D_Spectrum";
      translationFile += QString(imageObject).remove('_');
      if (m_imageType == UniformlySampledSpectrum) {
        translationFile += "Uniform";
      }
      else if (m_imageType == BinSetSpectrum) {
        translationFile += "BinSet";
      }
    }
    translationFile += ".trn";
    FileName translationFileName(translationFile);

    PvlToXmlTranslationManager xlator(*inputLabel, translationFileName.expanded());
    xlator.Auto(*m_domDoc);

    QDomElement rootElement = m_domDoc->documentElement();
    QDomElement fileAreaObservationalElement =
                    rootElement.firstChildElement("File_Area_Observational");

    // Calculate the core base/mult for the output cube
    double base = 0.0;
    double multiplier = 1.0;
    double outputMin, outputMax;

    double inputMin = (p_inputMinimum.size()) ? p_inputMinimum[0] : 0.0;
    double inputMax = (p_inputMaximum.size()) ? p_inputMaximum[0] : 0.0;

    for(unsigned int i = 0; i < p_inputMinimum.size(); i ++) {
      inputMin = std::min(inputMin, p_inputMinimum[i]);
      inputMax = std::max(inputMax, p_inputMaximum[i]);
    }

    outputMin = p_outputMinimum;
    outputMax = p_outputMaximum;

    if(p_inputMinimum.size() && ( p_pixelType == Isis::UnsignedByte ||
                                  p_pixelType == Isis::SignedWord   ||
                                  p_pixelType == Isis::UnsignedWord ) ) {
      multiplier = (inputMax - inputMin) / (outputMax - outputMin);
      base = inputMin - multiplier * outputMin;
    }

    if (!fileAreaObservationalElement.isNull()) {
      QDomElement arrayImageElement =
                      fileAreaObservationalElement.firstChildElement(imageObject);
      if (!arrayImageElement.isNull()) {

        // reorder axis elements. 
        // Translation order:  elements, axis_name, sequence_number
        // Correct order:      axis_name, elements, sequence_number
        QDomElement axisArrayElement = arrayImageElement.firstChildElement("Axis_Array");
        while( !axisArrayElement.isNull() ) {
          QDomElement axisNameElement = axisArrayElement.firstChildElement("axis_name");
          axisArrayElement.insertBefore(axisNameElement, 
                                        axisArrayElement.firstChildElement("elements"));
          axisArrayElement = axisArrayElement.nextSiblingElement("Axis_Array");
        }

        QDomElement elementArrayElement = m_domDoc->createElement("Element_Array");
        arrayImageElement.insertBefore(elementArrayElement,
                                         arrayImageElement.firstChildElement("Axis_Array"));

        QDomElement dataTypeElement = m_domDoc->createElement("data_type");
        PvlToXmlTranslationManager::setElementValue(dataTypeElement,
                                                    PDS4PixelType(p_pixelType, p_endianType));
        elementArrayElement.appendChild(dataTypeElement);

        QDomElement scalingFactorElement = m_domDoc->createElement("scaling_factor");
        PvlToXmlTranslationManager::setElementValue(scalingFactorElement,
                                                    toString(multiplier));
        elementArrayElement.appendChild(scalingFactorElement);

        QDomElement offsetElement = m_domDoc->createElement("value_offset");
        PvlToXmlTranslationManager::setElementValue(offsetElement,
                                                    toString(base));
        elementArrayElement.appendChild(offsetElement);
      }

      // Add the Special_Constants class to define ISIS special pixel values if pixel type is
      QDomElement specialConstantElement = m_domDoc->createElement("Special_Constants"); 
      arrayImageElement.insertAfter(specialConstantElement,
                                    arrayImageElement.lastChildElement("Axis_Array"));

      switch (p_pixelType) {
        case Real: 
          { QDomElement nullElement = m_domDoc->createElement("missing_constant");
          PvlToXmlTranslationManager::setElementValue(nullElement, QString::number(NULL4, 'g', 18));
          specialConstantElement.appendChild(nullElement);
        
          QDomElement highInstrumentSatElement = m_domDoc->createElement("high_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(highInstrumentSatElement, QString::number(HIGH_INSTR_SAT4, 'g', 18));
          specialConstantElement.appendChild(highInstrumentSatElement);

          QDomElement highRepresentationSatElement = m_domDoc->createElement("high_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(highRepresentationSatElement, QString::number(HIGH_REPR_SAT4, 'g', 18));
          specialConstantElement.appendChild(highRepresentationSatElement);

          QDomElement lowInstrumentSatElement = m_domDoc->createElement("low_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(lowInstrumentSatElement, QString::number(LOW_INSTR_SAT4, 'g', 18));
          specialConstantElement.appendChild(lowInstrumentSatElement);

          QDomElement lowRepresentationSatElement = m_domDoc->createElement("low_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(lowRepresentationSatElement, QString::number(LOW_REPR_SAT4, 'g', 18));
          specialConstantElement.appendChild(lowRepresentationSatElement); 
          break;}

        case UnsignedByte:
          { QDomElement nullElement = m_domDoc->createElement("missing_constant");
          PvlToXmlTranslationManager::setElementValue(nullElement, QString::number(NULL1, 'g', 18));
          specialConstantElement.appendChild(nullElement);
        
          QDomElement highInstrumentSatElement = m_domDoc->createElement("high_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(highInstrumentSatElement, QString::number(HIGH_INSTR_SAT1, 'g', 18));
          specialConstantElement.appendChild(highInstrumentSatElement);

          QDomElement highRepresentationSatElement = m_domDoc->createElement("high_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(highRepresentationSatElement, QString::number(HIGH_REPR_SAT1, 'g', 18));
          specialConstantElement.appendChild(highRepresentationSatElement);

          QDomElement lowInstrumentSatElement = m_domDoc->createElement("low_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(lowInstrumentSatElement, QString::number(LOW_INSTR_SAT1, 'g', 18));
          specialConstantElement.appendChild(lowInstrumentSatElement);

          QDomElement lowRepresentationSatElement = m_domDoc->createElement("low_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(lowRepresentationSatElement, QString::number(LOW_REPR_SAT1, 'g', 18));
          specialConstantElement.appendChild(lowRepresentationSatElement);
          break; }

        case SignedWord:
          { QDomElement nullElement = m_domDoc->createElement("missing_constant");
          PvlToXmlTranslationManager::setElementValue(nullElement, QString::number(NULL2, 'g', 18));
          specialConstantElement.appendChild(nullElement);
        
          QDomElement highInstrumentSatElement = m_domDoc->createElement("high_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(highInstrumentSatElement, QString::number(HIGH_INSTR_SAT2, 'g', 18));
          specialConstantElement.appendChild(highInstrumentSatElement);

          QDomElement highRepresentationSatElement = m_domDoc->createElement("high_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(highRepresentationSatElement, QString::number(HIGH_REPR_SAT2, 'g', 18));
          specialConstantElement.appendChild(highRepresentationSatElement);

          QDomElement lowInstrumentSatElement = m_domDoc->createElement("low_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(lowInstrumentSatElement, QString::number(LOW_INSTR_SAT2, 'g', 18));
          specialConstantElement.appendChild(lowInstrumentSatElement);

          QDomElement lowRepresentationSatElement = m_domDoc->createElement("low_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(lowRepresentationSatElement, QString::number(LOW_REPR_SAT2, 'g', 18));
          specialConstantElement.appendChild(lowRepresentationSatElement); 
          break; }

        case UnsignedWord:
          { QDomElement nullElement = m_domDoc->createElement("missing_constant");
          PvlToXmlTranslationManager::setElementValue(nullElement, QString::number(NULLU2, 'g', 18));
          specialConstantElement.appendChild(nullElement);
        
          QDomElement highInstrumentSatElement = m_domDoc->createElement("high_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(highInstrumentSatElement, QString::number(HIGH_INSTR_SATU2, 'g', 18));
          specialConstantElement.appendChild(highInstrumentSatElement);

          QDomElement highRepresentationSatElement = m_domDoc->createElement("high_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(highRepresentationSatElement, QString::number(HIGH_REPR_SATU2, 'g', 18));
          specialConstantElement.appendChild(highRepresentationSatElement);

          QDomElement lowInstrumentSatElement = m_domDoc->createElement("low_instrument_saturation");
          PvlToXmlTranslationManager::setElementValue(lowInstrumentSatElement, QString::number(LOW_INSTR_SATU2, 'g', 18));
          specialConstantElement.appendChild(lowInstrumentSatElement);

          QDomElement lowRepresentationSatElement = m_domDoc->createElement("low_representation_saturation");
          PvlToXmlTranslationManager::setElementValue(lowRepresentationSatElement, QString::number(LOW_REPR_SATU2, 'g', 18));
          specialConstantElement.appendChild(lowRepresentationSatElement); 
          break; }

        case None:
          break;

        default:
          break;
      }



      if (!m_pixelDescription.isEmpty()) {
        QDomElement descriptionElement = m_domDoc->createElement("description"); 
        PvlToXmlTranslationManager::setElementValue(descriptionElement,
                                                    m_pixelDescription);
        arrayImageElement.insertAfter(descriptionElement, arrayImageElement.lastChildElement());
      }
    }
  }


  void ProcessExportPds4::addSchema(QString xsd, QString xmlns, QString xmlnsURI) {
    // Add xmlns
    QDomElement root = m_domDoc->documentElement();
    root.setAttribute(xmlns, xmlnsURI);

    // Add to xsi:schemaLocation
    m_schemaLocation += " "; 
    m_schemaLocation += xmlnsURI;
    m_schemaLocation += " ";
    m_schemaLocation += xmlnsURI;
    m_schemaLocation += "/";
    m_schemaLocation += xsd;
    root.setAttribute("xsi:schemaLocation", m_schemaLocation);
  }


  void ProcessExportPds4::addSchema(QString sch, QString xsd, QString xmlns, QString xmlnsURI) {
    // Add xml-model
    QString xmlModel;
    xmlModel += "href=\"";
    xmlModel +=  xmlnsURI;
    xmlModel +=  "/";
    xmlModel +=  sch;
    xmlModel += "\" schematypens=\"http://purl.oclc.org/dsdl/schematron\"";
    QDomProcessingInstruction header =
        m_domDoc->createProcessingInstruction("xml-model", xmlModel);
    m_domDoc->insertAfter(header, m_domDoc->firstChild());

    // Add xmlns
    addSchema(xsd, xmlns, xmlnsURI);
  }


  void ProcessExportPds4::OutputLabel(std::ofstream &os) {
    os << m_domDoc->toString() << endl;
  }


  void ProcessExportPds4::StartProcess(std::ofstream &fout) {
    ProcessExport::StartProcess(fout);
  }


  QDomDocument &ProcessExportPds4::GetLabel() {
    if (m_domDoc->documentElement().isNull()) {
      QDomElement root = m_domDoc->createElement("Product_Observational");
      root.setAttribute("xmlns", "http://pds.nasa.gov/pds4/pds/v1");
      root.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance");
      root.setAttribute("xsi:schemaLocation",
                        "http://pds.nasa.gov/pds4/pds/v1 http://pds.nasa.gov/pds4/pds/v1");
      m_domDoc->appendChild(root);
    }
    return *m_domDoc;
  }
  
  
  void ProcessExportPds4::WritePds4(QString outFile) {
    
    FileName outputFile(outFile);

    // Name for output label
    QString path(outputFile.originalPath());
    QString name(outputFile.baseName());
    QString labelName = path + "/" + name + ".xml";

    // Name for output image
    QString imageName = outputFile.expanded();

    // If input file ends in .xml, the user entered a label name for the output file, not an
    // image name with a unique file extension. 
    if (QString::compare(outputFile.extension(), "xml", Qt::CaseInsensitive) == 0) {
      imageName = path + "/" + name + ".img";
    }

    QDomElement rootElement = m_domDoc->documentElement();
    QDomElement fileAreaObservationalElement =
                    rootElement.firstChildElement("File_Area_Observational");

    QDomElement fileElement = m_domDoc->createElement("File");
    fileAreaObservationalElement.insertBefore(fileElement, 
                                              fileAreaObservationalElement.firstChildElement());

    QDomElement fileNameElement = m_domDoc->createElement("file_name");
    PvlToXmlTranslationManager::setElementValue(fileNameElement, outputFile.name());
    fileElement.appendChild(fileNameElement);

//    QDomElement creationElement = m_domDoc->createElement("creation_date_time");
//    PvlToXmlTranslationManager::setElementValue(creationElement, );
//    fileElement.appendChild(creationElement);

    ofstream outputLabel(labelName.toLatin1().data());
    OutputLabel(outputLabel);
    outputLabel.close();
    
    ofstream outputImageFile(imageName.toLatin1().data());
    StartProcess(outputImageFile);
    outputImageFile.close();

    EndProcess();
  }


  void ProcessExportPds4::StandardAllMapping() {
    // Cartography
    // Get the input Isis cube label and find the Mapping group if it has one
    Pvl *inputLabel = InputCubes[0]->label();
    if(inputLabel->hasObject("IsisCube") &&
        !(inputLabel->findObject("IsisCube").hasGroup("Mapping"))) return;
    PvlGroup &inputMapping = inputLabel->findGroup("Mapping", Pvl::Traverse);

    addSchema("PDS4_CART_1900.sch", 
              "PDS4_CART_1900.xsd",
              "xmlns:cart", 
              "http://pds.nasa.gov/pds4/cart/v1"); 

    // Translate the projection specific keywords for a PDS IMAGE_MAP_PROJECTION
    Projection *proj = ProjectionFactory::Create(*inputLabel); 
    QString projName = proj->Name();
    try {
      PvlToXmlTranslationManager xlatorSpecProj(*inputLabel, 
                                                "$base/translations/pds4Export" + projName + ".trn");
      xlatorSpecProj.Auto(*m_domDoc);
    } 
    catch (IException &e) {
      QString msg = "Unable to export projection [" + projName + "] to PDS4 product. " + 
                     "This projection is not supported in ISIS3.";
      throw IException(e, IException::User, msg, _FILEINFO_);
    }

    // convert units.
    QStringList xmlPath;
    xmlPath << "Product_Observational" 
            << "Observation_Area" 
            << "Discipline_Area" 
            << "cart:Cartography" 
            << "cart:Map_Projection" 
            << "cart:Spatial_Reference_Information" 
            << "cart:Horizontal_Coordinate_System_Definition"
            << "cart:Geodetic_Model";

    QDomElement baseElement = m_domDoc->documentElement();
    QDomElement geodeticModelElement = getElement(xmlPath, baseElement);
    QDomElement semiMajorRadElement = geodeticModelElement.firstChildElement("cart:semi_major_radius");
    if (!semiMajorRadElement.isNull()) {

      QString units = semiMajorRadElement.attribute("unit");
      if( units.compare("km", Qt::CaseInsensitive) != 0 && units.compare("kilometers", Qt::CaseInsensitive) != 0) { 

        //if no units, assume in meters
        double dValue = toDouble(semiMajorRadElement.text());
        dValue /= 1000.0;
        PvlToXmlTranslationManager::resetElementValue(semiMajorRadElement, toString(dValue), "km");
      }
    }

    QDomElement semiMinorRadElement = geodeticModelElement.firstChildElement("cart:semi_minor_radius");
    if (!semiMinorRadElement.isNull()) {

      QString units = semiMinorRadElement.attribute("unit");
      if( units.compare("km", Qt::CaseInsensitive) != 0 && units.compare("kilometers", Qt::CaseInsensitive) != 0) { 
        // If no units, assume in meters
        double dValue = toDouble(semiMinorRadElement.text());
        dValue /= 1000.0;
        PvlToXmlTranslationManager::resetElementValue(semiMinorRadElement, toString(dValue), "km");
      }
    }

    QDomElement polarRadElement = geodeticModelElement.firstChildElement("cart:polar_radius");
    if (!polarRadElement.isNull()) {
      QString units = polarRadElement.attribute("unit");
      if( units.compare("km", Qt::CaseInsensitive) != 0 && units.compare("kilometers", Qt::CaseInsensitive) != 0) { 
        // If no units, assume in meters
        double dValue = toDouble(polarRadElement.text());
        dValue /= 1000.0;
        PvlToXmlTranslationManager::resetElementValue(polarRadElement, toString(dValue), "km");
      }
    }

    PvlKeyword &isisLonDir = inputMapping.findKeyword("LongitudeDirection");
    QString lonDir = isisLonDir[0];
    lonDir = lonDir.toUpper();
    
    // Add Lat/Lon range
    double maxLon, minLon, maxLat, minLat; 
    InputCubes[0]->latLonRange(minLat, maxLat, minLon, maxLon); 
    
    xmlPath.clear();
    xmlPath << "Product_Observational"
            << "Observation_Area" 
            << "Discipline_Area"
            << "cart:Cartography" 
            << "cart:Spatial_Domain"
            << "cart:Bounding_Coordinates";
    QDomElement boundingCoordElement = getElement(xmlPath, baseElement);
    QDomElement eastElement = boundingCoordElement.firstChildElement("cart:east_bounding_coordinate");
    QDomElement westElement = boundingCoordElement.firstChildElement("cart:west_bounding_coordinate");
    QDomElement northElement = boundingCoordElement.firstChildElement("cart:north_bounding_coordinate");
    QDomElement southElement = boundingCoordElement.firstChildElement("cart:south_bounding_coordinate");

    // Translation files currently handles Positive West case where east = min, west = max
    // so if positive east, swap min/max
    if(QString::compare(lonDir, "PositiveEast", Qt::CaseInsensitive) == 0) {
      // west min, east max
      PvlToXmlTranslationManager::resetElementValue(eastElement, toString(maxLon), "deg");
      PvlToXmlTranslationManager::resetElementValue(westElement, toString(minLon), "deg");
    }
    else {
      PvlToXmlTranslationManager::resetElementValue(eastElement, toString(minLon), "deg");
      PvlToXmlTranslationManager::resetElementValue(westElement, toString(maxLon), "deg");
    }

    PvlToXmlTranslationManager::resetElementValue(northElement, toString(maxLat), "deg");
    PvlToXmlTranslationManager::resetElementValue(southElement, toString(minLat), "deg");

    // longitude_of_central_meridian and latitude_of_projection_origin need to be converted to floats.
    xmlPath.clear();
    xmlPath << "Product_Observational"
            << "Observation_Area" 
            << "Discipline_Area"
            << "cart:Cartography" 
            << "cart:Spatial_Reference_Information"
            << "cart:Horizontal_Coordinate_System_Definition"
            << "cart:Planar"
            << "cart:Map_Projection";

    // The following is necessary because the full xmlPath differs depending on the projection used.
    QDomElement projectionElement = getElement(xmlPath, baseElement);
    QDomElement tempElement = projectionElement.firstChildElement();
    QDomElement nameElement = tempElement.nextSiblingElement();

    QDomElement longitudeElement = nameElement.firstChildElement("cart:longitude_of_central_meridian"); 
    QDomElement originElement = nameElement.firstChildElement("cart:latitude_of_projection_origin");

    double longitudeElementValue = longitudeElement.text().toDouble(); 
    double originElementValue = originElement.text().toDouble(); 

    // Only update the ouput formatting if there are no digits after the decimal point. 
    if (!longitudeElement.text().contains('.')) {
      QString toset1 = QString::number(longitudeElementValue, 'f', 1); 
      PvlToXmlTranslationManager::resetElementValue(longitudeElement, toset1, "deg"); 
    }

    if (!originElement.text().contains('.')) {
      QString toset2 = QString::number(originElementValue, 'f', 1); 
      PvlToXmlTranslationManager::resetElementValue(originElement, toset2, "deg");
    }
  }


  QDomElement ProcessExportPds4::getElement(QStringList xmlPath, QDomElement parent) {
    QDomElement baseElement = parent;
    if (baseElement.isNull()) {
      baseElement = m_domDoc->documentElement();
    }
    if (baseElement.isNull()) { 
      QString msg = "Unable to get element from empty XML document."; 
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    QString parentName = xmlPath[0];
    if (parentName != baseElement.tagName()) {
      QString msg = "The tag name of the parent element passed in "
                    "must be the first value in the given XML path."; 
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    for (int i = 1; i < xmlPath.size(); i++) {
      QString elementName = xmlPath[i];
      QDomElement nextElement = baseElement.firstChildElement(elementName);
      baseElement = nextElement;
    }
    return baseElement;
  }


  QString ProcessExportPds4::PDS4PixelType(PixelType pixelType, ByteOrder endianType) {
    QString pds4Type("UNK");
    if(p_pixelType == Isis::UnsignedByte) {
      pds4Type = "UnsignedByte";
    }
    else if((p_pixelType == Isis::UnsignedWord) && (p_endianType == Isis::Msb)) {
      pds4Type = "UnsignedMSB2";
    }
    else if((p_pixelType == Isis::UnsignedWord) && (p_endianType == Isis::Lsb)) {
      pds4Type = "UnsignedLSB2";
    }
    else if((p_pixelType == Isis::SignedWord) && (p_endianType == Isis::Msb)) {
      pds4Type = "SignedMSB2";
    }
    else if((p_pixelType == Isis::SignedWord) && (p_endianType == Isis::Lsb)) {
      pds4Type = "SignedLSB2";
    }
    else if((p_pixelType == Isis::Real) && (p_endianType == Isis::Msb)) {
      pds4Type = "IEEE754MSBSingle";
    }
    else if((p_pixelType == Isis::Real) && (p_endianType == Isis::Lsb)) {
      pds4Type = "IEEE754LSBSingle";
    }
    else {
      QString msg = "Unsupported PDS pixel type or sample size";
      throw IException(IException::User, msg, _FILEINFO_);
    }
    return pds4Type;
  }


  void ProcessExportPds4::addHistory(QString description, QString date, QString version) {
    // Check that at least the "Identification_Area" element exists.
    QDomElement identificationElement;
    QStringList identificationPath;
    identificationPath.append("Product_Observational");
    identificationPath.append("Identification_Area");
    try {
      identificationElement = getElement(identificationPath);
      if( identificationElement.isNull() ) {
        throw IException(IException::Unknown, "", _FILEINFO_);
      }
    }
    catch(IException &e) {
      QString msg = "Could not find Identification_Area element "
                    "to add modification history under.";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }

    // Check if the "Modification_History" element exists yet.
    // If not, create one.
    QDomElement historyElement = identificationElement.firstChildElement("Modification_History");
    if ( historyElement.isNull() ) {
      historyElement = m_domDoc->createElement("Modification_History");
      identificationElement.insertAfter( historyElement,
                                         identificationElement.lastChildElement() );
    }

    // Create the "Modification_Detail" element and add it to the end of the
    // "Modification_History" element.
    QDomElement detailElement = m_domDoc->createElement("Modification_Detail");

    QDomElement modDateElement = m_domDoc->createElement("modification_date");
    PvlToXmlTranslationManager::setElementValue(modDateElement, date);
    detailElement.appendChild(modDateElement);

    QDomElement versionIdElement = m_domDoc->createElement("version_id");
    PvlToXmlTranslationManager::setElementValue(versionIdElement, version);
    detailElement.appendChild(versionIdElement);

    QDomElement descriptionElement = m_domDoc->createElement("description");
    PvlToXmlTranslationManager::setElementValue(descriptionElement, description);
    detailElement.appendChild(descriptionElement);

    historyElement.insertAfter( detailElement,
                                historyElement.lastChildElement() );
  }


  void ProcessExportPds4::translateUnits(QDomDocument &label, QString transMapFile) {
    Pvl configPvl;
    try {
      configPvl.read(transMapFile);
    }
    catch(IException &e) {
      QString msg = "Failed to read unit translation config file [" + transMapFile + "].";
      throw IException(e, IException::Io, msg, _FILEINFO_);
    }

    QMap<QString, QString> transMap;
    try {
      transMap = createUnitMap(configPvl);
    }
    catch(IException &e) {
      QString msg = "Failed to load unit translation config file [" + transMapFile + "].";
      throw IException(e, IException::Unknown, msg, _FILEINFO_);
    }

    // Now that the map is filled, recursively search through the XML document
    // for units and translate them.
    try {
      translateChildUnits( label.documentElement(), transMap );
    }
    catch(IException &e) {
      QString msg = "Failed to translate units with config file [" + transMapFile + "].";
      throw IException(e, IException::Unknown, msg, _FILEINFO_);
    }
  }


  QMap<QString, QString> ProcessExportPds4::createUnitMap(Pvl configPvl) {
    QMap<QString, QString> transMap;
    for (int i = 0; i < configPvl.objects(); i++) {
      PvlObject unitObject = configPvl.object(i);
      for (int j = 0; j < unitObject.groups(); j++) {
        PvlGroup unitGroup = unitObject.group(j);
        if (!unitGroup.hasKeyword("PDS4_Unit")) {
          QString msg = "No PDS4 standard specified for for [" + unitGroup.name() + "]";
          throw IException(IException::Programmer, msg, _FILEINFO_);
        }
        PvlKeyword pds4Key = unitGroup["PDS4_Unit"];
        // Add the PDS4 format for when the format is already correct.
        // This also handles case issues such as KM instead of km.
        transMap.insert(pds4Key[0].toLower(), pds4Key[0]);

        // If there are ISIS versions with different formats then add those.
        if (unitGroup.hasKeyword("ISIS_Units")) {
          PvlKeyword isisKey = unitGroup["ISIS_Units"];
          for (int k = 0; k < isisKey.size() ; k++) {
            transMap.insert(isisKey[k].toLower(), pds4Key[0]);
          }
        }
      }
    }
    return transMap; 
  }


  void ProcessExportPds4::translateChildUnits(QDomElement parent, QMap<QString, QString> transMap) {
    QDomElement childElement = parent.firstChildElement();

    while( !childElement.isNull() ) {
      if ( childElement.hasAttribute("unit") ) {
        QString originalUnit = childElement.attribute("unit");
        if ( transMap.contains( originalUnit.toLower() ) ) {
          childElement.setAttribute("unit", transMap.value( originalUnit.toLower() ) );
        }
        else {
          QString msg = "Could not translate unit [" + originalUnit + "] to PDS4 format.";
          throw IException(IException::Unknown, msg, _FILEINFO_);
        }
      }
      translateChildUnits(childElement, transMap);
      childElement = childElement.nextSiblingElement();
    }

    // Base case: If there are no more children end return
    return;
  }


} // End of Isis namespace