diff --git a/Modules/IGTBase/src/mitkNavigationDataSet.cpp b/Modules/IGTBase/src/mitkNavigationDataSet.cpp
index 559fe3fc01..2c5558397f 100644
--- a/Modules/IGTBase/src/mitkNavigationDataSet.cpp
+++ b/Modules/IGTBase/src/mitkNavigationDataSet.cpp
@@ -1,190 +1,190 @@
 /*===================================================================
 
 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 "mitkNavigationDataSet.h"
 #include "mitkPointSet.h"
 #include "mitkBaseRenderer.h"
 
 mitk::NavigationDataSet::NavigationDataSet( unsigned int numberOfTools )
   : m_NavigationDataVectors(std::vector<std::vector<mitk::NavigationData::Pointer> >()), m_NumberOfTools(numberOfTools)
 {
 }
 
 mitk::NavigationDataSet::~NavigationDataSet( )
 {
 }
 
 bool mitk::NavigationDataSet::AddNavigationDatas( std::vector<mitk::NavigationData::Pointer> navigationDatas )
 {
   // test if tool with given index exist
   if ( navigationDatas.size() != m_NumberOfTools )
   {
     MITK_WARN("NavigationDataSet") << "Tried to add too many or too few navigation Datas to NavigationDataSet. " << m_NumberOfTools << " required, tried to add " << navigationDatas.size() << ".";
     return false;
   }
 
   // test for consistent timestamp
   if ( m_NavigationDataVectors.size() > 0)
   {
     for (std::vector<mitk::NavigationData::Pointer>::size_type i = 0; i < navigationDatas.size(); i++)
       if (navigationDatas[i]->GetIGTTimeStamp() <= m_NavigationDataVectors.back()[i]->GetIGTTimeStamp())
       {
         MITK_WARN("NavigationDataSet") << "IGTTimeStamp of new NavigationData should be newer than timestamp of last NavigationData.";
         return false;
       }
   }
 
   m_NavigationDataVectors.push_back(navigationDatas);
   return true;
 }
 
 mitk::NavigationData::Pointer mitk::NavigationDataSet::GetNavigationDataForIndex( unsigned int index, unsigned int toolIndex ) const
 {
   if ( index >= m_NavigationDataVectors.size() )
   {
     MITK_WARN("NavigationDataSet") << "There is no NavigationData available at index " << index << ".";
     return nullptr;
   }
 
   if ( toolIndex >= m_NavigationDataVectors.at(index).size() )
   {
     MITK_WARN("NavigationDataSet") << "There is NavigatitionData available at index " << index << " for tool " << toolIndex << ".";
     return nullptr;
   }
 
   return m_NavigationDataVectors.at(index).at(toolIndex);
 }
 
 // Method not yet supported, code below compiles but delivers wrong results
 //mitk::NavigationData::Pointer mitk::NavigationDataSet::GetNavigationDataBeforeTimestamp(
 //  mitk::NavigationData::TimeStampType timestamp, unsigned int toolIndex) const
 //{
 //  if ( toolIndex >= m_NavigationDataVectors.size() )
 //  {
 //    MITK_WARN("NavigationDataSet") << "There is no tool with index " << toolIndex << ".";
 //    return NULL;
 //  }
 //
 //  std::vector<mitk::NavigationData::Pointer>::const_iterator it;
 //
 //  // iterate through all NavigationData objects of the given tool index
 //  // till the timestamp of the NavigationData is greater then the given timestamp
 //  for (it = m_NavigationDataVectors.at(toolIndex).begin();
 //    it != m_NavigationDataVectors.at(toolIndex).end(); ++it)
 //  {
 //    if ( (*it)->GetIGTTimeStamp() > timestamp) { break; }
 //  }
 //
 //  // first element was greater than timestamp -> return null
 //  if ( it == m_NavigationDataVectors.at(toolIndex).begin() )
 //  {
 //    MITK_WARN("NavigationDataSet") << "No NavigationData was recorded before given timestamp.";
 //    return NULL;
 //  }
 //
 //  // return last element smaller than the given timestamp
 //  return *(it-1);
 //}
 
 std::vector< mitk::NavigationData::Pointer > mitk::NavigationDataSet::GetDataStreamForTool(unsigned int toolIndex)
 {
   if (toolIndex >= m_NumberOfTools )
   {
     MITK_WARN("NavigationDataSet") << "Invalid toolIndex: " << m_NumberOfTools << " Tools known, requested index " << toolIndex << "";
     return std::vector<mitk::NavigationData::Pointer>();
   }
 
   std::vector< mitk::NavigationData::Pointer > result;
 
   for(std::vector<std::vector<NavigationData::Pointer> >::size_type i = 0; i < m_NavigationDataVectors.size(); i++)
     result.push_back(m_NavigationDataVectors[i][toolIndex]);
 
   return result;
 }
 
 std::vector< mitk::NavigationData::Pointer > mitk::NavigationDataSet::GetTimeStep(unsigned int index) const
 {
   return m_NavigationDataVectors[index];
 }
 
 unsigned int mitk::NavigationDataSet::GetNumberOfTools() const
 {
   return m_NumberOfTools;
 }
 
 unsigned int mitk::NavigationDataSet::Size() const
 {
   return m_NavigationDataVectors.size();
 }
 
 // ---> methods necessary for BaseData
 void mitk::NavigationDataSet::SetRequestedRegionToLargestPossibleRegion()
 {
 }
 
 bool mitk::NavigationDataSet::RequestedRegionIsOutsideOfTheBufferedRegion()
 {
   return false;
 }
 
 bool mitk::NavigationDataSet::VerifyRequestedRegion()
 {
   return true;
 }
 
 void mitk::NavigationDataSet::SetRequestedRegion(const DataObject * )
 {
 }
 
 bool mitk::NavigationDataSet::IsEmpty() const
 {
   return (Size() == 0);
 }
 
 void mitk::NavigationDataSet::ConvertNavigationDataToPointSet() const
 {
   //iterate over all tools
-  for (int toolIndex = 0; toolIndex < this->GetNumberOfTools(); ++ toolIndex)
+  for (unsigned int toolIndex = 0; toolIndex < this->GetNumberOfTools(); ++ toolIndex)
   {
     mitk::PointSet::Pointer _tempPointSet = mitk::PointSet::New();
     //iterate over all time steps
-    for (int time = 0; time < m_NavigationDataVectors.size(); time++)
+    for (unsigned int time = 0; time < m_NavigationDataVectors.size(); time++)
     {
       _tempPointSet->InsertPoint(time,m_NavigationDataVectors[time][toolIndex]->GetPosition());
       MITK_DEBUG << m_NavigationDataVectors[time][toolIndex]->GetPosition() << " --- " << _tempPointSet->GetPoint(time);
     }
     mitk::DataNode::Pointer dn = mitk::DataNode::New();
     std::stringstream str;
     str << "NavigationData Tool " << toolIndex;
     dn->SetProperty("name", mitk::StringProperty::New(str.str()));
     dn->SetData(_tempPointSet);
     mitk::BaseRenderer::GetInstance(mitk::BaseRenderer::GetRenderWindowByName("stdmulti.widget4"))->GetDataStorage()->Add(dn);
   }
 }
 
 // <--- methods necessary for BaseData
 
 // ---> methods for Iterators
 
 mitk::NavigationDataSet::NavigationDataSetConstIterator mitk::NavigationDataSet::Begin() const
 {
   return m_NavigationDataVectors.cbegin();
 }
 
 mitk::NavigationDataSet::NavigationDataSetConstIterator mitk::NavigationDataSet::End() const
 {
   return m_NavigationDataVectors.cend();
 }