diff --git a/Modules/IGT/IO/mitkNavigationDataSetWriterCSV.cpp b/Modules/IGT/IO/mitkNavigationDataSetWriterCSV.cpp
index 6b3fe24c1f..18c682953c 100644
--- a/Modules/IGT/IO/mitkNavigationDataSetWriterCSV.cpp
+++ b/Modules/IGT/IO/mitkNavigationDataSetWriterCSV.cpp
@@ -1,74 +1,74 @@
 /*===================================================================
 
 The Medical Imaging Interaction Toolkit (MITK)
 
 Copyright (c) German Cancer Research Center,
 Division of Medical and Biological Informatics.
 All rights reserved.
 
 This software is distributed WITHOUT ANY WARRANTY; without
 even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.
 
 See LICENSE.txt or http://www.mitk.org for details.
 
 ===================================================================*/
 
 #include "mitkNavigationDataSetWriterCSV.h"
-
+#include <fstream>
 
 void mitk::NavigationDataSetWriterCSV::Write (std::string path, mitk::NavigationDataSet::Pointer data)
 {
   MITK_INFO << "Writing navigation data set to file: " << path;
   std::ofstream stream;
   stream.open (path.c_str(), std::ios_base::trunc);
 
   // Pass to Stream Handler
   Write(&stream, data);
   stream.close();
 }
 
 void mitk::NavigationDataSetWriterCSV::Write (std::ostream* stream, mitk::NavigationDataSet::Pointer data)
 {
   //write header
   int numberOfTools = data->GetNumberOfTools();
   for (unsigned int index = 0; index < numberOfTools; index++){ *stream << "TimeStamp_Tool" << index <<
                                                                            ";Valid_Tool" << index <<
                                                                            ";X_Tool" << index <<
                                                                            ";Y_Tool" << index <<
                                                                            ";Z_Tool" << index <<
                                                                            ";QX_Tool" << index <<
                                                                            ";QY_Tool" << index <<
                                                                            ";QZ_Tool" << index <<
                                                                            ";QR_Tool" << index << ";";}
   *stream << "\n";
 
   stream->precision(15); // rounding precision because we don't want to loose data.
 
   //write data
   MITK_INFO << "Number of timesteps: " << data->Size();
   for (int i=0; i<data->Size(); i++)
   {
     std::vector< mitk::NavigationData::Pointer > NavigationDatasOfCurrentStep = data->GetTimeStep(i);
     for (int toolIndex = 0; toolIndex < numberOfTools; toolIndex++)
     {
       mitk::NavigationData::Pointer nd = NavigationDatasOfCurrentStep.at(toolIndex);
       *stream          << nd->GetTimeStamp() << ";"
                        << nd->IsDataValid() << ";"
                        << nd->GetPosition()[0] << ";"
                        << nd->GetPosition()[1] << ";"
                        << nd->GetPosition()[2] << ";"
                        << nd->GetOrientation()[0] << ";"
                        << nd->GetOrientation()[1] << ";"
                        << nd->GetOrientation()[2] << ";"
                        << nd->GetOrientation()[3] << ";";
     }
     *stream << "\n";
   }
 }
 
 mitk::NavigationDataSetWriterCSV::NavigationDataSetWriterCSV()
 {}
 
 mitk::NavigationDataSetWriterCSV::~NavigationDataSetWriterCSV()
 {}