diff --git a/dune/vtk/datacollector.hh b/dune/vtk/datacollector.hh
index a5bd9fcc23e45fa868c1636c40ac64d27cb80763..6c384f0a4e71e026dc27c0e0effb3f5b1fdede79 100644
--- a/dune/vtk/datacollector.hh
+++ b/dune/vtk/datacollector.hh
@@ -42,6 +42,12 @@ public:
     asDerived().updateImpl();
   }
 
+  /// Return the number of overlapping elements
+  int ghostLevel () const
+  {
+    return asDerived().ghostLevelImpl();
+  }
+
   /// \brief Return a flat vector of point coordinates
   /**
    * All coordinates are extended to 3 components and concatenated.
@@ -104,7 +110,15 @@ protected: // default implementations
     return gridView_.size(0);
   }
 
-  void updateImpl () { /* do nothing */ }
+  void updateImpl ()
+  {
+    /* do nothing */
+  }
+
+  int ghostLevelImpl () const
+  {
+    return gridView_.overlapSize(0);
+  }
 
   // Evaluate `fct` in center of cell
   template <class T, class GlobalFunction>
diff --git a/dune/vtk/writers/vtkimagedatawriter.hh b/dune/vtk/writers/vtkimagedatawriter.hh
index 43bed33dad0626af3c2619907b38f58e7ac2747c..ada9fd941bbc167880421ec03d88c0ad25c137c8 100644
--- a/dune/vtk/writers/vtkimagedatawriter.hh
+++ b/dune/vtk/writers/vtkimagedatawriter.hh
@@ -14,7 +14,11 @@
 
 namespace Dune { namespace experimental
 {
-  /// File-Writer for VTK .vtu files
+  /// File-Writer for ImageData VTK .vti files
+  /**
+   * Requirement:
+   * - DataCollector must be a model of \ref StructuredDataCollector
+   **/
   template <class GridView, class DataCollector = StructuredDataCollector<GridView>>
   class VtkImageDataWriter
       : public VtkWriterInterface<GridView, DataCollector>
diff --git a/dune/vtk/writers/vtkrectilineargridwriter.hh b/dune/vtk/writers/vtkrectilineargridwriter.hh
index 3c7c62e29c6b064217355d17c616ff5f7dde7a1b..d92f41bf636a1801f17501a1c846f861a6b7576f 100644
--- a/dune/vtk/writers/vtkrectilineargridwriter.hh
+++ b/dune/vtk/writers/vtkrectilineargridwriter.hh
@@ -14,7 +14,11 @@
 
 namespace Dune { namespace experimental
 {
-  /// File-Writer for VTK .vtu files
+  /// File-Writer for RectilinearGrid VTK .vtr files
+  /**
+   * Requirement:
+   * - DataCollector must be a model of \ref StructuredDataCollector
+   **/
   template <class GridView, class DataCollector = StructuredDataCollector<GridView>>
   class VtkRectilinearGridWriter
       : public VtkWriterInterface<GridView, DataCollector>
diff --git a/dune/vtk/writers/vtkstructuredgridwriter.hh b/dune/vtk/writers/vtkstructuredgridwriter.hh
index 8fcd788f78a60106771f7862e87bb4c9d8b4e453..0a0d47602a667676e07394242026f4ae95707057 100644
--- a/dune/vtk/writers/vtkstructuredgridwriter.hh
+++ b/dune/vtk/writers/vtkstructuredgridwriter.hh
@@ -14,7 +14,11 @@
 
 namespace Dune { namespace experimental
 {
-  /// File-Writer for VTK .vtu files
+  /// File-Writer for StructuredGrid VTK .vts files
+  /**
+   * Requirement:
+   * - DataCollector must be a model of \ref StructuredDataCollector
+   **/
   template <class GridView, class DataCollector = StructuredDataCollector<GridView>>
   class VtkStructuredGridWriter
       : public VtkWriterInterface<GridView, DataCollector>
diff --git a/dune/vtk/writers/vtkunstructuredgridwriter.hh b/dune/vtk/writers/vtkunstructuredgridwriter.hh
index 44a4aa80af1c7249affd005f323d6783f27334ca..049a495b0d4322ec67d1cc72ab8607b3b5ddda26 100644
--- a/dune/vtk/writers/vtkunstructuredgridwriter.hh
+++ b/dune/vtk/writers/vtkunstructuredgridwriter.hh
@@ -15,6 +15,10 @@
 namespace Dune { namespace experimental
 {
   /// File-Writer for VTK .vtu files
+  /**
+   * Requirement:
+   * - DataCollector must be a model of \ref DataCollector
+   **/
   template <class GridView, class DataCollector = DefaultDataCollector<GridView>>
   class VtkUnstructuredGridWriter
       : public VtkWriterInterface<GridView, DataCollector>