Index: Core/Components/test/Core.Components.DotSpatial.Test/Converter/MapMultiLineDataConverterTest.cs
===================================================================
diff -u
--- Core/Components/test/Core.Components.DotSpatial.Test/Converter/MapMultiLineDataConverterTest.cs	(revision 0)
+++ Core/Components/test/Core.Components.DotSpatial.Test/Converter/MapMultiLineDataConverterTest.cs	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -0,0 +1,120 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using Core.Common.Base.Geometry;
+using Core.Common.TestUtil;
+using Core.Components.DotSpatial.Converter;
+using Core.Components.DotSpatial.TestUtil;
+using Core.Components.Gis.Data;
+using DotSpatial.Controls;
+using NUnit.Framework;
+
+namespace Core.Components.DotSpatial.Test.Converter
+{
+    [TestFixture]
+    public class MapMultiLineDataConverterTest
+    {
+        [Test]
+        public void DefaultConstructor_IsMapMultiLineDataConverter()
+        {
+            // Call
+            var converter = new MapMultiLineDataConverter();
+
+            // Assert
+            Assert.IsInstanceOf<MapDataConverter<MapMultiLineData>>(converter);
+        }
+
+        [Test]
+        public void CanConvertMapData_MapLineData_ReturnTrue()
+        {
+            // Setup
+            var converter = new MapMultiLineDataConverter();
+            var lineData = new MapMultiLineData(Enumerable.Empty<IEnumerable<Point2D>>());
+
+            // Call
+            var canConvert = converter.CanConvertMapData(lineData);
+
+            // Assert
+            Assert.IsTrue(canConvert);
+        }
+
+        [Test]
+        public void CanConvertMapData_TestMapData_ReturnsFalse()
+        {
+            // Setup
+            var converter = new MapMultiLineDataConverter();
+            var mapData = new TestMapData();
+
+            // Call
+            var canConvert = converter.CanConvertMapData(mapData);
+
+            // Assert
+            Assert.IsFalse(canConvert);
+        }
+
+        [Test]
+        public void Convert_DataNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            var testConverter = new MapMultiLineDataConverter();
+
+            // Call
+            TestDelegate test = () => testConverter.Convert(null);
+
+            // Assert
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentNullException>(test, "Null data cannot be converted into feature sets.");
+        }
+
+        [Test]
+        public void Convert_DataCannotBeConverted_ThrowsArgumentException()
+        {
+            // Setup
+            var testConverter = new MapMultiLineDataConverter();
+            var testMapData = new TestMapData();
+            var expectedMessage = string.Format("The data of type {0} cannot be converted by this converter.", testMapData.GetType());
+
+            // Precondition
+            Assert.IsFalse(testConverter.CanConvertMapData(testMapData));
+
+            // Call
+            TestDelegate test = () => testConverter.Convert(testMapData);
+
+            // Assert
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentException>(test, expectedMessage);
+        }
+
+        [Test]
+        public void Convert_RandomMultiLineData_ReturnsNewMapLineLayerList()
+        {
+            // Setup
+            var converter = new MapMultiLineDataConverter();
+            var random = new Random(21);
+            var pointCount = random.Next(5, 10);
+            var lineCount = random.Next(5, 10);
+            var points = new Collection<Point2D>();
+            var lines = new Collection<IEnumerable<Point2D>>();
+
+            for (int li = 0; li < lineCount; li++)
+            {
+                for (int pi = 0; pi < pointCount; pi++)
+                {
+                    points.Add(new Point2D(random.NextDouble(), random.NextDouble()));
+                }
+                lines.Add(points);
+            }
+
+            var lineData = new MapMultiLineData(lines);
+
+            // Call
+            var mapLayers = converter.Convert(lineData);
+
+            // Assert
+            Assert.IsInstanceOf<IList<IMapFeatureLayer>>(mapLayers);
+            Assert.AreEqual(1, mapLayers.Count);
+            var layer = mapLayers[0];
+            Assert.IsInstanceOf<MapLineLayer>(layer);
+            Assert.AreEqual(lineCount, layer.DataSet.Features.Count);
+        }
+    }
+}
\ No newline at end of file
Index: Core/Components/test/Core.Components.DotSpatial.Test/Core.Components.DotSpatial.Test.csproj
===================================================================
diff -u -rca53cf67b367c4d2fab058aa39b3fe8de536dc7f -r3607710d80a1f77bf97f81b10869074b765686a0
--- Core/Components/test/Core.Components.DotSpatial.Test/Core.Components.DotSpatial.Test.csproj	(.../Core.Components.DotSpatial.Test.csproj)	(revision ca53cf67b367c4d2fab058aa39b3fe8de536dc7f)
+++ Core/Components/test/Core.Components.DotSpatial.Test/Core.Components.DotSpatial.Test.csproj	(.../Core.Components.DotSpatial.Test.csproj)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -99,6 +99,7 @@
     <Reference Include="System.Core" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Converter\MapMultiLineDataConverterTest.cs" />
     <Compile Include="Converter\MapDataCollectionConverterTest.cs" />
     <Compile Include="Converter\MapLineDataConverterTest.cs" />
     <Compile Include="Converter\MapPolygonDataConverterTest.cs" />
Index: Core/Components/test/Core.Components.Gis.Test/Core.Components.Gis.Test.csproj
===================================================================
diff -u -r2310b1df9f3fcfa1e01ee6eec2206a4dd0f38f5c -r3607710d80a1f77bf97f81b10869074b765686a0
--- Core/Components/test/Core.Components.Gis.Test/Core.Components.Gis.Test.csproj	(.../Core.Components.Gis.Test.csproj)	(revision 2310b1df9f3fcfa1e01ee6eec2206a4dd0f38f5c)
+++ Core/Components/test/Core.Components.Gis.Test/Core.Components.Gis.Test.csproj	(.../Core.Components.Gis.Test.csproj)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -41,6 +41,7 @@
     <Reference Include="System.Core" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Data\MapMultiLineDataTest.cs" />
     <Compile Include="Data\MapDataCollectionTest.cs" />
     <Compile Include="Data\MapDataTest.cs" />
     <Compile Include="Data\MapLineDataTest.cs" />
Index: Core/Components/test/Core.Components.Gis.Test/Data/MapMultiLineDataTest.cs
===================================================================
diff -u
--- Core/Components/test/Core.Components.Gis.Test/Data/MapMultiLineDataTest.cs	(revision 0)
+++ Core/Components/test/Core.Components.Gis.Test/Data/MapMultiLineDataTest.cs	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using Core.Common.Base.Geometry;
+using Core.Common.TestUtil;
+using Core.Components.Gis.Data;
+
+using NUnit.Framework;
+
+namespace Core.Components.Gis.Test.Data
+{
+    [TestFixture]
+    public class MapMultiLineDataTest
+    {
+        [Test]
+        public void Constructor_NullCollection_ThrowsArgumentNullException()
+        {
+            // Call
+            TestDelegate test = () => new MapMultiLineData(null);
+
+            // Assert
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentNullException>(test, string.Format("A point collection is required when creating a subclass of {0}.", typeof(PointBasedMapData)));
+        }
+
+        [Test]
+        public void Constructor_WithEmptyCollection_CreatesNewMapLineData()
+        {
+            // Setup
+            var collection = new Collection<IEnumerable<Point2D>>();
+
+            // Call
+            var data = new MapMultiLineData(collection);
+
+            // Assert
+            Assert.IsInstanceOf<MapData>(data);
+            Assert.AreNotSame(collection, data.Lines);
+        }
+
+        [Test]
+        public void Constructor_WithPoints_CreatesNewMapLineData()
+        {
+            // Setup
+            var lines = CreateTestLines();
+
+            // Call
+            var data = new MapMultiLineData(lines);
+
+            // Assert
+            Assert.IsInstanceOf<MapData>(data);
+            Assert.AreNotSame(lines, data.Lines);
+            CollectionAssert.AreEqual(lines, data.Lines);
+        }
+
+        private static IEnumerable<IEnumerable<Point2D>> CreateTestLines()
+        {
+            return new Collection<IEnumerable<Point2D>>
+            {
+                new Collection<Point2D> {
+                    new Point2D(0.0, 1.1),
+                    new Point2D(1.0, 2.1),
+                    new Point2D(1.6, 1.6)
+                }
+            };
+        }
+    }
+}
\ No newline at end of file
Index: Core/Plugins/src/Core.Plugins.DotSpatial/Legend/MapLegendView.cs
===================================================================
diff -u -r61de56d96afe43d6ba193795c084a07fdff78b34 -r3607710d80a1f77bf97f81b10869074b765686a0
--- Core/Plugins/src/Core.Plugins.DotSpatial/Legend/MapLegendView.cs	(.../MapLegendView.cs)	(revision 61de56d96afe43d6ba193795c084a07fdff78b34)
+++ Core/Plugins/src/Core.Plugins.DotSpatial/Legend/MapLegendView.cs	(.../MapLegendView.cs)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -126,6 +126,16 @@
                 CanInsert = BaseMapCanInsert,
                 OnDrop = BaseMapOnDrop
             });
+
+            treeViewControl.RegisterTreeNodeInfo(new TreeNodeInfo<MapMultiLineData>
+            {
+                Text = mapMultiLineData => DotSpatialResources.MapData_MultiLine_data_label,
+                Image = mapMultiLineData => DotSpatialResources.LineIcon,
+                CanDrag = (mapMultiLineData, parentData) => true,
+                CanCheck = mapMultiLineData => true,
+                IsChecked = mapMultiLineData => mapMultiLineData.IsVisible,
+                OnNodeChecked = MapMultiLineDataOnNodeChecked
+            });
         }
 
         #region MapData
@@ -145,6 +155,18 @@
             PointBasedMapDataOnNodeChecked(mapPolygonData, parentData);
         }
 
+        private void MapMultiLineDataOnNodeChecked(MapMultiLineData mapMultiLineData, object parentData)
+        {
+            mapMultiLineData.IsVisible = !mapMultiLineData.IsVisible;
+            mapMultiLineData.NotifyObservers();
+
+            var observableParent = parentData as IObservable;
+            if (observableParent != null)
+            {
+                observableParent.NotifyObservers();
+            }
+        }
+
         private void PointBasedMapDataOnNodeChecked(PointBasedMapData pointBasedMapData, object parentData)
         {
             pointBasedMapData.IsVisible = !pointBasedMapData.IsVisible;
Index: Core/Plugins/src/Core.Plugins.DotSpatial/Properties/Resources.Designer.cs
===================================================================
diff -u -r3aa114b55dd6caa46890a54af64fba874497c135 -r3607710d80a1f77bf97f81b10869074b765686a0
--- Core/Plugins/src/Core.Plugins.DotSpatial/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 3aa114b55dd6caa46890a54af64fba874497c135)
+++ Core/Plugins/src/Core.Plugins.DotSpatial/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -1,7 +1,7 @@
 //------------------------------------------------------------------------------
 // <auto-generated>
 //     This code was generated by a tool.
-//     Runtime Version:4.0.30319.42000
+//     Runtime Version:4.0.30319.34209
 //
 //     Changes to this file may cause incorrect behavior and will be lost if
 //     the code is regenerated.
@@ -109,6 +109,15 @@
         }
         
         /// <summary>
+        ///   Looks up a localized string similar to Lijnen.
+        /// </summary>
+        public static string MapData_MultiLine_data_label {
+            get {
+                return ResourceManager.GetString("MapData_MultiLine_data_label", resourceCulture);
+            }
+        }
+        
+        /// <summary>
         ///   Looks up a localized string similar to Punten.
         /// </summary>
         public static string MapData_Point_data_label {
Index: Core/Plugins/src/Core.Plugins.DotSpatial/Properties/Resources.resx
===================================================================
diff -u -r3aa114b55dd6caa46890a54af64fba874497c135 -r3607710d80a1f77bf97f81b10869074b765686a0
--- Core/Plugins/src/Core.Plugins.DotSpatial/Properties/Resources.resx	(.../Resources.resx)	(revision 3aa114b55dd6caa46890a54af64fba874497c135)
+++ Core/Plugins/src/Core.Plugins.DotSpatial/Properties/Resources.resx	(.../Resources.resx)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -181,4 +181,7 @@
   <data name="ZoomToAllIcon" type="System.Resources.ResXFileRef, System.Windows.Forms">
     <value>..\Resources\zoomextents.png;System.Drawing.Bitmap, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a</value>
   </data>
+  <data name="MapData_MultiLine_data_label" xml:space="preserve">
+    <value>Lijnen</value>
+  </data>
 </root>
\ No newline at end of file
Index: Core/Plugins/test/Core.Plugins.DotSpatial.Test/Legend/MapLegendViewTest.cs
===================================================================
diff -u -r61f3b606ba0003553fe583462bab6e493043be5e -r3607710d80a1f77bf97f81b10869074b765686a0
--- Core/Plugins/test/Core.Plugins.DotSpatial.Test/Legend/MapLegendViewTest.cs	(.../MapLegendViewTest.cs)	(revision 61f3b606ba0003553fe583462bab6e493043be5e)
+++ Core/Plugins/test/Core.Plugins.DotSpatial.Test/Legend/MapLegendViewTest.cs	(.../MapLegendViewTest.cs)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Windows.Forms;
+using Core.Common.Base.Geometry;
 using Core.Common.Controls.TreeView;
 using Core.Common.Controls.Views;
 using Core.Common.Utils.Reflection;
@@ -41,7 +43,7 @@
         }
 
         [Test]
-        public void Data_MapData_DataSet()
+        public void Data_MapDataCollection_DataSet()
         {
             // Setup
             var view = new MapLegendView();
@@ -55,7 +57,68 @@
             Assert.IsInstanceOf<MapData>(view.Data);
         }
 
+
         [Test]
+        public void Data_MapPointData_DataSet()
+        {
+            // Setup
+            var view = new MapLegendView();
+            var mapData = new MapPointData(Enumerable.Empty<Point2D>());
+
+            // Call
+            view.Data = mapData;
+
+            // Assert
+            Assert.AreSame(mapData, view.Data);
+            Assert.IsInstanceOf<MapData>(view.Data);
+        }
+
+        [Test]
+        public void Data_MapLineData_DataSet()
+        {
+            // Setup
+            var view = new MapLegendView();
+            var mapData = new MapLineData(Enumerable.Empty<Point2D>());
+
+            // Call
+            view.Data = mapData;
+
+            // Assert
+            Assert.AreSame(mapData, view.Data);
+            Assert.IsInstanceOf<MapData>(view.Data);
+        }
+
+        [Test]
+        public void Data_MapPolygonData_DataSet()
+        {
+            // Setup
+            var view = new MapLegendView();
+            var mapData = new MapPolygonData(Enumerable.Empty<Point2D>());
+
+            // Call
+            view.Data = mapData;
+
+            // Assert
+            Assert.AreSame(mapData, view.Data);
+            Assert.IsInstanceOf<MapData>(view.Data);
+        }
+
+        [Test]
+        public void Data_MapMultiLineData_DataSet()
+        {
+            // Setup
+            var view = new MapLegendView();
+            var mapData = new MapMultiLineData(Enumerable.Empty<IEnumerable<Point2D>>());
+
+            // Call
+            view.Data = mapData;
+
+            // Assert
+            Assert.AreSame(mapData, view.Data);
+            Assert.IsInstanceOf<MapData>(view.Data);
+        }
+
+        [Test]
         public void Data_ForNull_NullSet()
         {
             // Setup
Index: Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingFailureMechanismView.cs
===================================================================
diff -u -rdb376befd1575a80aa5f4d3e84f803e132ac1a75 -r3607710d80a1f77bf97f81b10869074b765686a0
--- Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingFailureMechanismView.cs	(.../PipingFailureMechanismView.cs)	(revision db376befd1575a80aa5f4d3e84f803e132ac1a75)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingFailureMechanismView.cs	(.../PipingFailureMechanismView.cs)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -57,17 +57,41 @@
             }
             set
             {
-                data = value as PipingFailureMechanismContext;
+                var newValue = value as PipingFailureMechanismContext;
 
-                if (data != null)
+                DetachFromData();
+                data = newValue;
+                SetDataToMap();
+                AttachToData();
+            }
+        }
+
+        private void AttachToData()
+        {
+            if (data != null)
+            {
+                data.Parent.Attach(this);
+                var surfaceLines = data.WrappedData.SurfaceLines as IObservable;
+                if (surfaceLines != null)
                 {
-                    data.Parent.Detach(this);
-                    SetDataToMap();
-                    data.Parent.Attach(this);
+                    surfaceLines.Attach(this);
                 }
             }
         }
 
+        private void DetachFromData()
+        {
+            if (data != null)
+            {
+                data.Parent.Detach(this);
+                var surfaceLines = data.WrappedData.SurfaceLines as IObservable;
+                if (surfaceLines != null)
+                {
+                    surfaceLines.Detach(this);
+                }
+            }
+        }
+
         public IMap Map
         {
             get
@@ -80,14 +104,22 @@
         {
             var mapDataList = new List<MapData>();
 
-            if (HasReferenceLinePoints())
+            if (data != null)
             {
-                mapDataList.Add(GetReferenceLineData());
-            }
+                if (HasReferenceLinePoints())
+                {
+                    mapDataList.Add(GetReferenceLineData());
+                }
 
-            if (HasHydraulicBoundaryLocations())
-            {
-                mapDataList.Add(GetHydraulicBoundaryLocations());
+                if (HasHydraulicBoundaryLocations())
+                {
+                    mapDataList.Add(GetHydraulicBoundaryLocations());
+                }
+
+                if (HasSurfaceLines())
+                {
+                    mapDataList.Add(GetSurfaceLines());
+                }
             }
 
             map.Data = new MapDataCollection(mapDataList);
@@ -105,6 +137,12 @@
             return new MapPointData(hrLocations);
         }
 
+        private MapData GetSurfaceLines()
+        {
+            IEnumerable<IEnumerable<Point2D>> surfaceLines = data.WrappedData.SurfaceLines.Select(sl => sl.Points.Select(p => new Point2D(p.X, p.Y)));
+            return new MapMultiLineData(surfaceLines);
+        }
+
         private bool HasReferenceLinePoints()
         {
             return data.Parent.ReferenceLine != null && data.Parent.ReferenceLine.Points.Any();
@@ -115,6 +153,11 @@
             return data.Parent.HydraulicBoundaryDatabase != null && data.Parent.HydraulicBoundaryDatabase.Locations.Any();
         }
 
+        private bool HasSurfaceLines()
+        {
+            return data.WrappedData.SurfaceLines.Any();
+        }
+
         public void UpdateObserver()
         {
             if (data != null)
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingFailureMechanismViewTest.cs
===================================================================
diff -u -r0965fa8f8a151c07b31ea35ab888c4ef969638e6 -r3607710d80a1f77bf97f81b10869074b765686a0
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingFailureMechanismViewTest.cs	(.../PipingFailureMechanismViewTest.cs)	(revision 0965fa8f8a151c07b31ea35ab888c4ef969638e6)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingFailureMechanismViewTest.cs	(.../PipingFailureMechanismViewTest.cs)	(revision 3607710d80a1f77bf97f81b10869074b765686a0)
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Windows.Forms;
 using Core.Common.Base;
@@ -78,7 +79,7 @@
             var assessmentSectionBase = new TestAssessmentSectionBase
             {
                 HydraulicBoundaryDatabase = new HydraulicBoundaryDatabase(),
-                ReferenceLine = new ReferenceLine()
+                ReferenceLine = new ReferenceLine(),
             };
             assessmentSectionBase.HydraulicBoundaryDatabase.Locations.Add(new HydraulicBoundaryLocation(1, "test", 1.0, 2.0));
             assessmentSectionBase.ReferenceLine.SetGeometry(new List<Point2D>
@@ -88,6 +89,8 @@
             });
 
             var pipingFailureMechanism = new PipingFailureMechanism();
+            pipingFailureMechanism.SurfaceLines.Add(new RingtoetsPipingSurfaceLine());
+
             var pipingContext = new PipingFailureMechanismContext(pipingFailureMechanism, assessmentSectionBase);
 
             // Call
@@ -98,8 +101,9 @@
             Assert.IsInstanceOf<MapDataCollection>(map.Data);
             var mapData = map.Data as MapDataCollection;
             Assert.IsNotNull(mapData);
-            Assert.IsTrue(mapData.List.Any(md => md is MapPointData));
-            Assert.IsTrue(mapData.List.Any(md => md is MapLineData));
+            Assert.AreEqual(1, mapData.List.Count(md => md is MapPointData));
+            Assert.AreEqual(1, mapData.List.Count(md => md is MapLineData));
+            Assert.AreEqual(1, mapData.List.Count(md => md is MapMultiLineData));
         }
 
         [Test]
@@ -170,7 +174,6 @@
             view.Data = pipingContext;
             var mapData = map.Data;
 
-            assessmentSectionBase.HydraulicBoundaryDatabase = new HydraulicBoundaryDatabase();
             assessmentSectionBase.ReferenceLine.SetGeometry(new List<Point2D>
             {
                 new Point2D(2.0, 5.0),
@@ -187,6 +190,45 @@
         }
 
         [Test]
+        public void UpdateObserver_SurfaceLinesUpdated_SetNewMapDataData()
+        {
+            // Setup
+            var view = new PipingFailureMechanismView();
+            var map = (BaseMap)view.Controls[0];
+
+            var mocks = new MockRepository();
+            var observer = mocks.StrictMock<IObserver>();
+            observer.Expect(o => o.UpdateObserver());
+
+            mocks.ReplayAll();
+
+            var assessmentSectionBase = new TestAssessmentSectionBase();
+            var pipingFailureMechanism = new PipingFailureMechanism();
+            ((IObservable)pipingFailureMechanism.SurfaceLines).Attach(observer);
+
+            var pipingContext = new PipingFailureMechanismContext(pipingFailureMechanism, assessmentSectionBase);
+
+            view.Data = pipingContext;
+            var mapData = map.Data;
+
+            var surfaceLine = new RingtoetsPipingSurfaceLine();
+            surfaceLine.SetGeometry(new Collection<Point3D>
+            {
+                new Point3D(1,2,3),
+                new Point3D(1,2,3)
+            });
+            pipingFailureMechanism.SurfaceLines.Add(surfaceLine);
+
+            // Call
+            ((IObservable)pipingFailureMechanism.SurfaceLines).NotifyObservers();
+
+            // Assert
+            Assert.AreNotEqual(mapData, map.Data);
+            Assert.IsInstanceOf<MapDataCollection>(map.Data);
+            mocks.VerifyAll();
+        }
+
+        [Test]
         public void UpdateObserver_OtherAssessmentSectionUpdated_MapDataNotUpdated()
         {
             // Setup
@@ -271,8 +313,8 @@
 
             assessmentSectionBase.Attach(observer);
 
-            MapData dataBeforeUpdate = map.Data;
             view.Data = null;
+            MapData dataBeforeUpdate = map.Data;
 
             assessmentSectionBase.ReferenceLine = new ReferenceLine();
             assessmentSectionBase.ReferenceLine.SetGeometry(new List<Point2D>
@@ -285,11 +327,46 @@
             assessmentSectionBase.NotifyObservers();
 
             // Assert
-            Assert.IsNull(view.Data);
             Assert.AreEqual(dataBeforeUpdate, map.Data);
             mocks.VerifyAll();
         }
 
+        [Test]
+        public void NotifyObservers_DataUpdatedNotifyObserversOnOldData_NoUpdateInViewData()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            AssessmentSectionBase oldAssessmentSectionMock = mocks.Stub<AssessmentSectionBase>();
+            AssessmentSectionBase newAssessmentSectionMock = mocks.Stub<AssessmentSectionBase>();
+            mocks.ReplayAll();
+
+            newAssessmentSectionMock.ReferenceLine = new ReferenceLine();
+            newAssessmentSectionMock.ReferenceLine.SetGeometry(new[]
+            {
+                    new Point2D(2,4),
+                    new Point2D(3,4)
+            });
+
+            var oldPipingFailureMechanismContext = new PipingFailureMechanismContext(new PipingFailureMechanism(), oldAssessmentSectionMock);
+            var newPipingFailureMechanismContext = new PipingFailureMechanismContext(new PipingFailureMechanism(), newAssessmentSectionMock);
+            var view = new PipingFailureMechanismView();
+            var map = (BaseMap)view.Controls[0];
+
+            view.Data = oldPipingFailureMechanismContext;
+            view.Data = newPipingFailureMechanismContext;
+            MapData dataBeforeUpdate = map.Data;
+
+            newAssessmentSectionMock.ReferenceLine.SetGeometry(Enumerable.Empty<Point2D>());
+
+            // Call
+            oldAssessmentSectionMock.NotifyObservers();
+
+            // Assert
+            Assert.AreEqual(dataBeforeUpdate, map.Data);
+
+            mocks.VerifyAll();
+        }
+
         private class TestAssessmentSectionBase : AssessmentSectionBase
         {
             public override IEnumerable<IFailureMechanism> GetFailureMechanisms()