Index: Core/Common/src/Core.Common.Base/Core.Common.Base.csproj
===================================================================
diff -u -r07b0e83704b56684d617cd6e8b8570417654912a -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Core/Common/src/Core.Common.Base/Core.Common.Base.csproj	(.../Core.Common.Base.csproj)	(revision 07b0e83704b56684d617cd6e8b8570417654912a)
+++ Core/Common/src/Core.Common.Base/Core.Common.Base.csproj	(.../Core.Common.Base.csproj)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -93,6 +93,7 @@
     <Compile Include="Data\ProjectComparer.cs" />
     <Compile Include="Geometry\Point2D.cs" />
     <Compile Include="Geometry\Point3D.cs" />
+    <Compile Include="Geometry\Point3DExtensions.cs" />
     <Compile Include="Geometry\Segment2D.cs" />
     <Compile Include="Geometry\Segment2DIntersectSegment2DResult.cs" />
     <Compile Include="IO\FileImporterBase.cs" />
Index: Core/Common/src/Core.Common.Base/Geometry/Point3DExtensions.cs
===================================================================
diff -u
--- Core/Common/src/Core.Common.Base/Geometry/Point3DExtensions.cs	(revision 0)
+++ Core/Common/src/Core.Common.Base/Geometry/Point3DExtensions.cs	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -0,0 +1,84 @@
+// Copyright (C) Stichting Deltares 2016. All rights reserved.
+//
+// This file is part of Ringtoets.
+//
+// Ringtoets is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using MathNet.Numerics.LinearAlgebra;
+
+namespace Core.Common.Base.Geometry
+{
+    /// <summary>
+    /// Extension methods for <see cref="Point3D"/>.
+    /// </summary>
+    public static class Point3DExtensions
+    {
+        /// <summary>
+        /// This method defines the 'spanning line' as the 2D vector going from <paramref name="startWorldCoordinate"/> 
+        /// to <paramref name="endWorldCoordinate"/>. Then the <paramref name="worldCoordinate"/> is projected onto
+        /// this vector. Then the local coordinate is determined by taking the length of each vector along the 'spanning line'.
+        /// </summary>
+        /// <param name="worldCoordinate">The point to project.</param>
+        /// <param name="startWorldCoordinate">The start of the 'spanning line'.</param>
+        /// <param name="endWorldCoordinate">The end point of the 'spanning line'.</param>
+        /// <exception cref="ArgumentNullException">Thrown when either:
+        /// <list type="bullet">
+        /// <item><paramref name="worldCoordinate"/> is <c>null</c>.</item>
+        /// <item><paramref name="startWorldCoordinate"/> is <c>null</c>.</item>
+        /// <item><paramref name="endWorldCoordinate"/> is <c>null</c>.</item>
+        /// </list>
+        /// </exception>
+        /// <exception cref="ArgumentException">Thrown when the <paramref name="startWorldCoordinate"/> 
+        /// and the <paramref name="endWorldCoordinate"/> are the same.</exception>
+        public static Point2D ProjectIntoLocalCoordinates(this Point3D worldCoordinate, Point2D startWorldCoordinate, Point2D endWorldCoordinate)
+        {
+            if (worldCoordinate == null)
+            {
+                throw new ArgumentNullException("worldCoordinate");
+            }
+            if (startWorldCoordinate == null)
+            {
+                throw new ArgumentNullException("startWorldCoordinate");
+            }
+            if (endWorldCoordinate == null)
+            {
+                throw new ArgumentNullException("endWorldCoordinate");
+            }
+
+            Point2D worldCoordinate2D = new Point2D(worldCoordinate.X, worldCoordinate.Y);
+            Vector<double> vectorToPoint = (worldCoordinate2D - startWorldCoordinate);
+
+            // Determine the 'spanning line' vector:
+            Vector<double> spanningVector = endWorldCoordinate - startWorldCoordinate;
+            double spanningVectorDotProduct = spanningVector.DotProduct(spanningVector);
+            double length = Math.Sqrt(spanningVectorDotProduct);
+
+            if (Math.Abs(length) < 1e-6)
+            {
+                throw new ArgumentException("The startWorldCoordinate and endWorldCoordinate can't be the same.");
+            }
+
+            // Project vector onto the 'spanning vector' to determine it's X coordinate in local coordinates:
+            double projectOnSpanningVectorFactor = (vectorToPoint.DotProduct(spanningVector)) / spanningVectorDotProduct;
+            double localCoordinateX = projectOnSpanningVectorFactor * length;
+
+            return new Point2D(localCoordinateX, worldCoordinate.Z);
+        }
+    }
+}
\ No newline at end of file
Index: Core/Common/test/Core.Common.Base.Test/Core.Common.Base.Test.csproj
===================================================================
diff -u -r07b0e83704b56684d617cd6e8b8570417654912a -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Core/Common/test/Core.Common.Base.Test/Core.Common.Base.Test.csproj	(.../Core.Common.Base.Test.csproj)	(revision 07b0e83704b56684d617cd6e8b8570417654912a)
+++ Core/Common/test/Core.Common.Base.Test/Core.Common.Base.Test.csproj	(.../Core.Common.Base.Test.csproj)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -85,6 +85,7 @@
     <Compile Include="Data\RoundedDoubleTest.cs" />
     <Compile Include="Geometry\Math2DTest.cs" />
     <Compile Include="Geometry\Point2DTest.cs" />
+    <Compile Include="Geometry\Point3DExtensionsTest.cs" />
     <Compile Include="Geometry\Point3DTest.cs" />
     <Compile Include="Geometry\Segment2DIntersectSegment2DResultTest.cs" />
     <Compile Include="Geometry\Segment2DTest.cs" />
Index: Core/Common/test/Core.Common.Base.Test/Geometry/Point3DExtensionsTest.cs
===================================================================
diff -u
--- Core/Common/test/Core.Common.Base.Test/Geometry/Point3DExtensionsTest.cs	(revision 0)
+++ Core/Common/test/Core.Common.Base.Test/Geometry/Point3DExtensionsTest.cs	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -0,0 +1,106 @@
+// Copyright (C) Stichting Deltares 2016. All rights reserved.
+//
+// This file is part of Ringtoets.
+//
+// Ringtoets is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using Core.Common.Base.Geometry;
+using Core.Common.TestUtil;
+using NUnit.Framework;
+
+namespace Core.Common.Base.Test.Geometry
+{
+    [TestFixture]
+    public class Point3DExtensionsTest
+    {
+        [Test]
+        public void ProjectIntoLocalCoordinates_WorldCoordinateNull_ThrowsArgumentNullException()
+        {
+            // Call
+            TestDelegate call = () => Point3DExtensions.ProjectIntoLocalCoordinates(null, new Point2D(1.0, 2.0), new Point2D(3.0, 4.0));
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(call);
+            Assert.AreEqual("worldCoordinate", exception.ParamName);
+        }
+
+        [Test]
+        public void ProjectIntoLocalCoordinates_StartWorldCoordinateNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            Point3D point = new Point3D(1.0, 2.0, 3.0);
+
+            // Call
+            TestDelegate call = () => point.ProjectIntoLocalCoordinates(null, new Point2D(3.0, 4.0));
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(call);
+            Assert.AreEqual("startWorldCoordinate", exception.ParamName);
+        }
+
+        [Test]
+        public void ProjectIntoLocalCoordinates_EndWorldCoordinateNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            Point3D point = new Point3D(1.0, 2.0, 3.0);
+
+            // Call
+            TestDelegate call = () => point.ProjectIntoLocalCoordinates(new Point2D(1.0, 2.0), null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(call);
+            Assert.AreEqual("endWorldCoordinate", exception.ParamName);
+        }
+
+        [Test]
+        public void ProjectIntoLocalCoordinates_WorldCoordinateSameAsStartAndEndWordlCoordinate_ThrowsArgumentException()
+        {
+            // Setup
+            const double originalZ = 3.3;
+            Point3D point = new Point3D(1.1, 2.2, originalZ);
+
+            Point2D startAndEndPoint = new Point2D(point.X, point.Y);
+
+            // Call
+            TestDelegate call = () => point.ProjectIntoLocalCoordinates(startAndEndPoint, startAndEndPoint);
+
+            // Assert
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentException>(call, "The startWorldCoordinate and endWorldCoordinate can't be the same.");
+        }
+
+        [Test]
+        public void ProjectIntoLocalCoordinates_GeometryWithMultiplePoints_ProjectPointsOntoLzPlaneKeepingOriginalZ()
+        {
+            // Setup
+            Point2D startPoint = new Point2D(1.0, 1.0);
+            Point3D pointToConvert = new Point3D(2.0, 3.0, 4.4); // Outlier from line specified by extrema
+            Point2D endPoint = new Point2D(3.0, 4.0);
+
+            // Call
+            Point2D convertedPoint = pointToConvert.ProjectIntoLocalCoordinates(startPoint, endPoint);
+
+            // Assert
+            var length = Math.Sqrt(2 * 2 + 3 * 3);
+            const double pointToConvertCoordinateFactor = (2.0 * 1.0 + 3.0 * 2.0) / (2.0 * 2.0 + 3.0 * 3.0);
+            double expectedX = pointToConvertCoordinateFactor * length;
+
+            Assert.AreEqual(new Point2D(expectedX, pointToConvert.Z), convertedPoint);
+        }
+    }
+}
\ No newline at end of file
Index: Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingChartDataFactory.cs
===================================================================
diff -u -r02b8ab97baeb969e7e4008124fe05ffd944e2142 -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingChartDataFactory.cs	(.../PipingChartDataFactory.cs)	(revision 02b8ab97baeb969e7e4008124fe05ffd944e2142)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingChartDataFactory.cs	(.../PipingChartDataFactory.cs)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -112,14 +112,14 @@
         /// <param name="ditchPolderSide">The <see cref="Point3D"/> for which to create <see cref="ChartData"/>.</param>
         /// <returns><see cref="ChartData"/> based on the <paramref name="ditchPolderSide"/>.</returns>
         /// /// <exception cref="ArgumentNullException">Thrown when <paramref name="ditchPolderSide"/> is <c>null</c>.</exception>
-        public static ChartData CreateDitchPolderSide(Point3D ditchPolderSide)
+        public static ChartData CreateDitchPolderSide(RingtoetsPipingSurfaceLine surfaceLine)
         {
-            if (ditchPolderSide == null)
+            if (surfaceLine == null)
             {
-                throw new ArgumentNullException("ditchPolderSide");
+                throw new ArgumentNullException("surfaceLine");
             }
 
-            return CreatePoint(ditchPolderSide, PipingDataResources.CharacteristicPoint_DitchPolderSide, new ChartPointStyle(Color.Red, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
+            return CreateLocalPoint(surfaceLine.DitchPolderSide, surfaceLine, PipingDataResources.CharacteristicPoint_DitchPolderSide, new ChartPointStyle(Color.Red, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
         }
 
         /// <summary>
@@ -128,14 +128,14 @@
         /// <param name="bottomDitchPolderSide">The <see cref="Point3D"/> for which to create <see cref="ChartData"/>.</param>
         /// <returns><see cref="ChartData"/> based on the <paramref name="bottomDitchPolderSide"/>.</returns>
         /// /// <exception cref="ArgumentNullException">Thrown when <paramref name="bottomDitchPolderSide"/> is <c>null</c>.</exception>
-        public static ChartData CreateBottomDitchPolderSide(Point3D bottomDitchPolderSide)
+        public static ChartData CreateBottomDitchPolderSide(RingtoetsPipingSurfaceLine surfaceLine)
         {
-            if (bottomDitchPolderSide == null)
+            if (surfaceLine == null)
             {
-                throw new ArgumentNullException("bottomDitchPolderSide");
+                throw new ArgumentNullException("surfaceLine");
             }
 
-            return CreatePoint(bottomDitchPolderSide, PipingDataResources.CharacteristicPoint_BottomDitchPolderSide, new ChartPointStyle(Color.Blue, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
+            return CreateLocalPoint(surfaceLine.BottomDitchPolderSide, surfaceLine, PipingDataResources.CharacteristicPoint_BottomDitchPolderSide, new ChartPointStyle(Color.Blue, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
         }
 
         /// <summary>
@@ -144,14 +144,14 @@
         /// <param name="bottomDitchDikeSide">The <see cref="Point3D"/> for which to create <see cref="ChartData"/>.</param>
         /// <returns><see cref="ChartData"/> based on the <paramref name="bottomDitchDikeSide"/>.</returns>
         /// /// <exception cref="ArgumentNullException">Thrown when <paramref name="bottomDitchDikeSide"/> is <c>null</c>.</exception>
-        public static ChartData CreateBottomDitchDikeSide(Point3D bottomDitchDikeSide)
+        public static ChartData CreateBottomDitchDikeSide(RingtoetsPipingSurfaceLine surfaceLine)
         {
-            if (bottomDitchDikeSide == null)
+            if (surfaceLine == null)
             {
-                throw new ArgumentNullException("bottomDitchDikeSide");
+                throw new ArgumentNullException("surfaceLine");
             }
 
-            return CreatePoint(bottomDitchDikeSide, PipingDataResources.CharacteristicPoint_BottomDitchDikeSide, new ChartPointStyle(Color.Green, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
+            return CreateLocalPoint(surfaceLine.BottomDitchDikeSide, surfaceLine, PipingDataResources.CharacteristicPoint_BottomDitchDikeSide, new ChartPointStyle(Color.Green, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
         }
 
         /// <summary>
@@ -160,14 +160,14 @@
         /// <param name="ditchDikeSide">The <see cref="Point3D"/> for which to create <see cref="ChartData"/>.</param>
         /// <returns><see cref="ChartData"/> based on the <paramref name="ditchDikeSide"/>.</returns>
         /// /// <exception cref="ArgumentNullException">Thrown when <paramref name="ditchDikeSide"/> is <c>null</c>.</exception>
-        public static ChartData CreateDitchDikeSide(Point3D ditchDikeSide)
+        public static ChartData CreateDitchDikeSide(RingtoetsPipingSurfaceLine surfaceLine)
         {
-            if (ditchDikeSide == null)
+            if (surfaceLine == null)
             {
-                throw new ArgumentNullException("ditchDikeSide");
+                throw new ArgumentNullException("surfaceLine");
             }
 
-            return CreatePoint(ditchDikeSide, PipingDataResources.CharacteristicPoint_DitchDikeSide, new ChartPointStyle(Color.Purple, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
+            return CreateLocalPoint(surfaceLine.DitchDikeSide, surfaceLine, PipingDataResources.CharacteristicPoint_DitchDikeSide, new ChartPointStyle(Color.Purple, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
         }
 
         /// <summary>
@@ -176,14 +176,14 @@
         /// <param name="dikeToeAtRiver">The <see cref="Point3D"/> for which to create <see cref="ChartData"/>.</param>
         /// <returns><see cref="ChartData"/> based on the <paramref name="dikeToeAtRiver"/>.</returns>
         /// /// <exception cref="ArgumentNullException">Thrown when <paramref name="dikeToeAtRiver"/> is <c>null</c>.</exception>
-        public static ChartData CreateDikeToeAtRiver(Point3D dikeToeAtRiver)
+        public static ChartData CreateDikeToeAtRiver(RingtoetsPipingSurfaceLine surfaceLine)
         {
-            if (dikeToeAtRiver == null)
+            if (surfaceLine == null)
             {
-                throw new ArgumentNullException("dikeToeAtRiver");
+                throw new ArgumentNullException("surfaceLine");
             }
 
-            return CreatePoint(dikeToeAtRiver, PipingDataResources.CharacteristicPoint_DikeToeAtRiver, new ChartPointStyle(Color.Orange, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
+            return CreateLocalPoint(surfaceLine.DikeToeAtRiver, surfaceLine, PipingDataResources.CharacteristicPoint_DikeToeAtRiver, new ChartPointStyle(Color.Orange, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
         }
 
         /// <summary>
@@ -192,21 +192,23 @@
         /// <param name="dikeToeAtPolder">The <see cref="Point3D"/> for which to create <see cref="ChartData"/>.</param>
         /// <returns><see cref="ChartData"/> based on the <paramref name="dikeToeAtPolder"/>.</returns>
         /// /// <exception cref="ArgumentNullException">Thrown when <paramref name="dikeToeAtPolder"/> is <c>null</c>.</exception>
-        public static ChartData CreateDikeToeAtPolder(Point3D dikeToeAtPolder)
+        public static ChartData CreateDikeToeAtPolder(RingtoetsPipingSurfaceLine surfaceLine)
         {
-            if (dikeToeAtPolder == null)
+            if (surfaceLine == null)
             {
-                throw new ArgumentNullException("dikeToeAtPolder");
+                throw new ArgumentNullException("surfaceLine");
             }
 
-            return CreatePoint(dikeToeAtPolder, PipingDataResources.CharacteristicPoint_DikeToeAtPolder, new ChartPointStyle(Color.Silver, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
+            return CreateLocalPoint(surfaceLine.DikeToeAtPolder, surfaceLine, PipingDataResources.CharacteristicPoint_DikeToeAtPolder, new ChartPointStyle(Color.Silver, 8, Color.Transparent, 0, ChartPointSymbol.Circle));
         }
 
-        private static ChartData CreatePoint(Point3D dikeToeAtRiver, string name, ChartPointStyle style)
+        private static ChartData CreateLocalPoint(Point3D worldPoint, RingtoetsPipingSurfaceLine surfaceLine, string name, ChartPointStyle style)
         {
+            Point2D firstPoint = Point3DToPoint2D(surfaceLine.Points.First());
+            Point2D lastPoint = Point3DToPoint2D(surfaceLine.Points.Last());
             return new ChartPointData(new[]
             {
-                Point3DToPoint2D(dikeToeAtRiver)
+                worldPoint.ProjectIntoLocalCoordinates(firstPoint, lastPoint)
             }, name)
             {
                 Style = style
@@ -215,7 +217,7 @@
 
         private static Point2D Point3DToPoint2D(Point3D point3D)
         {
-            return new Point2D(point3D.X, point3D.Z);
+            return new Point2D(point3D.X, point3D.Y);
         }
     }
 }
\ No newline at end of file
Index: Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingInputView.cs
===================================================================
diff -u -r02b8ab97baeb969e7e4008124fe05ffd944e2142 -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingInputView.cs	(.../PipingInputView.cs)	(revision 02b8ab97baeb969e7e4008124fe05ffd944e2142)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Forms/Views/PipingInputView.cs	(.../PipingInputView.cs)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -120,14 +120,14 @@
             if (data != null)
             {
                 // Bottom most layer
+                surfaceLineData = AddOrUpdateChartData(surfaceLineData, GetSurfaceLineChartData());
                 ditchPolderSideData = AddOrUpdateChartData(ditchPolderSideData, GetDitchPolderSideData());
                 bottomDitchPolderSidePointData = AddOrUpdateChartData(bottomDitchPolderSidePointData, GetBottomDitchPolderSideData());
                 bottomDitchDikeSidePointData = AddOrUpdateChartData(bottomDitchDikeSidePointData, GetBottomDitchDikeSideData());
                 ditchDikeSidePointData = AddOrUpdateChartData(ditchDikeSidePointData, GetDitchDikeSideData());
                 dikeToeAtRiverPointData = AddOrUpdateChartData(dikeToeAtRiverPointData, GetDikeToeAtRiverData());
                 dikeToeAtPolderPointData = AddOrUpdateChartData(dikeToeAtPolderPointData, GetDikeToeAtPolderData());
                 entryPointData = AddOrUpdateChartData(entryPointData, GetEntryPointChartData());
-                surfaceLineData = AddOrUpdateChartData(surfaceLineData, GetSurfaceLineChartData());
                 // Top most layer
             }
 
@@ -158,7 +158,7 @@
             {
                 return PipingChartDataFactory.CreateEmptyPointData(PipingDataResources.CharacteristicPoint_DitchPolderSide);
             }
-            return PipingChartDataFactory.CreateDitchPolderSide(data.SurfaceLine.DitchPolderSide);
+            return PipingChartDataFactory.CreateDitchPolderSide(data.SurfaceLine);
         }
 
         private ChartData GetBottomDitchPolderSideData()
@@ -167,7 +167,7 @@
             {
                 return PipingChartDataFactory.CreateEmptyPointData(PipingDataResources.CharacteristicPoint_BottomDitchPolderSide);
             }
-            return PipingChartDataFactory.CreateBottomDitchPolderSide(data.SurfaceLine.BottomDitchPolderSide);
+            return PipingChartDataFactory.CreateBottomDitchPolderSide(data.SurfaceLine);
         }
 
         private ChartData GetBottomDitchDikeSideData()
@@ -176,7 +176,7 @@
             {
                 return PipingChartDataFactory.CreateEmptyPointData(PipingDataResources.CharacteristicPoint_BottomDitchDikeSide);
             }
-            return PipingChartDataFactory.CreateBottomDitchDikeSide(data.SurfaceLine.BottomDitchDikeSide);
+            return PipingChartDataFactory.CreateBottomDitchDikeSide(data.SurfaceLine);
         }
 
         private ChartData GetDitchDikeSideData()
@@ -185,7 +185,7 @@
             {
                 return PipingChartDataFactory.CreateEmptyPointData(PipingDataResources.CharacteristicPoint_DitchDikeSide);
             }
-            return PipingChartDataFactory.CreateDitchDikeSide(data.SurfaceLine.DitchDikeSide);
+            return PipingChartDataFactory.CreateDitchDikeSide(data.SurfaceLine);
         }
 
         private ChartData GetDikeToeAtRiverData()
@@ -194,7 +194,7 @@
             {
                 return PipingChartDataFactory.CreateEmptyPointData(PipingDataResources.CharacteristicPoint_DikeToeAtRiver);
             }
-            return PipingChartDataFactory.CreateDikeToeAtRiver(data.SurfaceLine.DikeToeAtRiver);
+            return PipingChartDataFactory.CreateDikeToeAtRiver(data.SurfaceLine);
         }
 
         private ChartData GetDikeToeAtPolderData()
@@ -203,7 +203,7 @@
             {
                 return PipingChartDataFactory.CreateEmptyPointData(PipingDataResources.CharacteristicPoint_DikeToeAtPolder);
             }
-            return PipingChartDataFactory.CreateDikeToeAtPolder(data.SurfaceLine.DikeToeAtPolder);
+            return PipingChartDataFactory.CreateDikeToeAtPolder(data.SurfaceLine);
         }
 
         private ChartData AddOrUpdateChartData(ChartData oldChartData, ChartData newChartData)
Index: Ringtoets/Piping/src/Ringtoets.Piping.IO/SurfaceLines/PipingSurfaceLinesCsvReader.cs
===================================================================
diff -u -rbbf8e2a3fb6e709c7d7a5ddbd955575f83720cc0 -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Ringtoets/Piping/src/Ringtoets.Piping.IO/SurfaceLines/PipingSurfaceLinesCsvReader.cs	(.../PipingSurfaceLinesCsvReader.cs)	(revision bbf8e2a3fb6e709c7d7a5ddbd955575f83720cc0)
+++ Ringtoets/Piping/src/Ringtoets.Piping.IO/SurfaceLines/PipingSurfaceLinesCsvReader.cs	(.../PipingSurfaceLinesCsvReader.cs)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -213,8 +213,8 @@
         /// <exception cref="LineParseException">Surface line geometry is invalid.</exception>
         private void CheckIfGeometryIsValid(RingtoetsPipingSurfaceLine surfaceLine)
         {
-            CheckReclinging(surfaceLine);
             CheckZeroLength(surfaceLine);
+            CheckReclinging(surfaceLine);
         }
 
         private void CheckZeroLength(RingtoetsPipingSurfaceLine surfaceLine)
Index: Ringtoets/Piping/src/Ringtoets.Piping.Primitives/RingtoetsPipingSurfaceLine.cs
===================================================================
diff -u -r93ca6aa3bd94ccb82da7d62f13cc9fa009f1443c -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Ringtoets/Piping/src/Ringtoets.Piping.Primitives/RingtoetsPipingSurfaceLine.cs	(.../RingtoetsPipingSurfaceLine.cs)	(revision 93ca6aa3bd94ccb82da7d62f13cc9fa009f1443c)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Primitives/RingtoetsPipingSurfaceLine.cs	(.../RingtoetsPipingSurfaceLine.cs)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -289,21 +289,16 @@
                 return Enumerable.Empty<Point2D>();
             }
 
-            var localCoordinatesX = new double[count];
-            localCoordinatesX[0] = 0.0;
-            if (count > 1)
+            Point3D first = Points.First();
+            if (count == 1)
             {
-                ProjectPointsAfterFirstOntoSpanningLine(localCoordinatesX);
+                return new[] { new Point2D(0.0, first.Z)};
             }
 
-            var result = new Point2D[count];
-            for (int i = 0; i < count; i++)
-            {
-                var x = localCoordinatesX[i];
-                var y = geometryPoints[i].Z;
-                result[i] = new Point2D(x, y);
-            }
-            return result;
+            Point3D last = Points.Last();
+            Point2D firstPoint = new Point2D(first.X, first.Y);
+            Point2D lastPoint = new Point2D(last.X, last.Y);
+            return Points.Select(p => p.ProjectIntoLocalCoordinates(firstPoint, lastPoint));
         }
 
         public override string ToString()
@@ -367,40 +362,5 @@
                 throw new ArgumentOutOfRangeException("localCoordinateL", outOfRangeMessage);
             }
         }
-
-        /// <summary>
-        /// This method defines the 'spanning line' as the 2D vector going from start to end
-        /// of the surface line points. Then all except the first point is projected onto
-        /// this vector. Then the local coordinates are determined by taking the length of
-        /// each vector along the 'spanning line'.
-        /// </summary>
-        /// <param name="localCoordinatesX">The array into which the projected X-coordinate 
-        /// values should be stored. Its <see cref="Array.Length"/> should be the same as
-        /// the collection-size of <see cref="Points"/>.</param>
-        private void ProjectPointsAfterFirstOntoSpanningLine(double[] localCoordinatesX)
-        {
-            // Determine the vectors from the first coordinate to each other coordinate point 
-            // in the XY world coordinate plane:
-            Point2D[] worldCoordinates = Points.Select(p => new Point2D(p.X, p.Y)).ToArray();
-            var worldCoordinateVectors = new Vector<double>[worldCoordinates.Length - 1];
-            for (int i = 1; i < worldCoordinates.Length; i++)
-            {
-                worldCoordinateVectors[i - 1] = worldCoordinates[i] - worldCoordinates[0];
-            }
-
-            // Determine the 'spanning line' vector:
-            Vector<double> spanningVector = worldCoordinateVectors[worldCoordinateVectors.Length - 1];
-            double spanningVectorDotProduct = spanningVector.DotProduct(spanningVector);
-            double length = Math.Sqrt(spanningVectorDotProduct);
-
-            // Project each vector onto the 'spanning vector' to determine it's X coordinate in local coordinates:
-            for (int i = 0; i < worldCoordinateVectors.Length - 1; i++)
-            {
-                double projectOnSpanningVectorFactor = (worldCoordinateVectors[i].DotProduct(spanningVector)) /
-                                                       (spanningVectorDotProduct);
-                localCoordinatesX[i + 1] = projectOnSpanningVectorFactor * length;
-            }
-            localCoordinatesX[localCoordinatesX.Length - 1] = length;
-        }
     }
 }
\ No newline at end of file
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingChartDataFactoryTest.cs
===================================================================
diff -u -r2206475a63c65a3af17ad81352699de1ca2cadcf -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingChartDataFactoryTest.cs	(.../PipingChartDataFactoryTest.cs)	(revision 2206475a63c65a3af17ad81352699de1ca2cadcf)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingChartDataFactoryTest.cs	(.../PipingChartDataFactoryTest.cs)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -176,25 +176,34 @@
 
             // Assert 
             var exception = Assert.Throws<ArgumentNullException>(call);
-            Assert.AreEqual("ditchPolderSide", exception.ParamName);
+            Assert.AreEqual("surfaceLine", exception.ParamName);
         }
 
         [Test]
         public void CreateDitchPolderSide_GivenDitchPolderSide_ReturnsChartDataWithDefaultStyling()
         {
             // Setup
-            Point3D ditchPolderSide = new Point3D(1.0, 4.3, 6.4);
+            Point3D ditchPolderSide = new Point3D(1.2, 2.3, 4.0);
+            var points = new[]
+            {
+                new Point3D(1.2, 2.3, 4.0),
+                new Point3D(2.7, 2.0, 6.0)
+            };
 
+            var surfaceLine = new RingtoetsPipingSurfaceLine();
+            surfaceLine.SetGeometry(points);
+            surfaceLine.SetDitchPolderSideAt(ditchPolderSide);
+
             // Call
-            ChartData data = PipingChartDataFactory.CreateDitchPolderSide(ditchPolderSide);
+            ChartData data = PipingChartDataFactory.CreateDitchPolderSide(surfaceLine);
 
             // Assert
             Assert.IsInstanceOf<ChartPointData>(data);
             ChartPointData chartPointData = (ChartPointData)data;
             Assert.AreEqual(1, chartPointData.Points.Count());
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DitchPolderSide, chartPointData.Name);
 
-            AssertEqualPointCollections(new[] { new Point2D(ditchPolderSide.X, ditchPolderSide.Z) }, chartPointData.Points);
+            AssertEqualLocalPointCollection(ditchPolderSide, surfaceLine, chartPointData.Points);
 
             AssertEqualStyle(chartPointData.Style, Color.Red, 8, Color.Transparent, 0, ChartPointSymbol.Circle);
         }
@@ -203,29 +212,38 @@
         public void CreateBottomDitchPolderSide_BottomDitchPolderSideNull_ThrowsArgumentNullException()
         {
             // Call
-            TestDelegate call = () => PipingChartDataFactory.CreateDitchPolderSide(null);
+            TestDelegate call = () => PipingChartDataFactory.CreateBottomDitchPolderSide(null);
 
             // Assert 
             var exception = Assert.Throws<ArgumentNullException>(call);
-            Assert.AreEqual("ditchPolderSide", exception.ParamName);
+            Assert.AreEqual("surfaceLine", exception.ParamName);
         }
 
         [Test]
         public void CreateBottomDitchPolderSide_GivenBottomDitchPolderSide_ReturnsChartDataWithDefaultStyling()
         {
             // Setup
-            Point3D bottomDitchPolderSide = new Point3D(1.0, 4.3, 6.4);
+            Point3D bottomDitchPolderSide = new Point3D(1.2, 2.3, 4.0);
+            var points = new[]
+            {
+                new Point3D(1.2, 2.3, 4.0),
+                new Point3D(2.7, 2.0, 6.0)
+            };
 
+            var surfaceLine = new RingtoetsPipingSurfaceLine();
+            surfaceLine.SetGeometry(points);
+            surfaceLine.SetBottomDitchPolderSideAt(bottomDitchPolderSide);
+
             // Call
-            ChartData data = PipingChartDataFactory.CreateBottomDitchPolderSide(bottomDitchPolderSide);
+            ChartData data = PipingChartDataFactory.CreateBottomDitchPolderSide(surfaceLine);
 
             // Assert
             Assert.IsInstanceOf<ChartPointData>(data);
             ChartPointData chartPointData = (ChartPointData)data;
             Assert.AreEqual(1, chartPointData.Points.Count());
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_BottomDitchPolderSide, chartPointData.Name);
 
-            AssertEqualPointCollections(new[] { new Point2D(bottomDitchPolderSide.X, bottomDitchPolderSide.Z) }, chartPointData.Points);
+            AssertEqualLocalPointCollection(bottomDitchPolderSide, surfaceLine, chartPointData.Points);
 
             AssertEqualStyle(chartPointData.Style, Color.Blue, 8, Color.Transparent, 0, ChartPointSymbol.Circle);
         }
@@ -238,25 +256,34 @@
 
             // Assert 
             var exception = Assert.Throws<ArgumentNullException>(call);
-            Assert.AreEqual("bottomDitchDikeSide", exception.ParamName);
+            Assert.AreEqual("surfaceLine", exception.ParamName);
         }
 
         [Test]
         public void CreateBottomDitchDikeSide_GivenBottomDitchDikeSide_ReturnsChartDataWithDefaultStyling()
         {
             // Setup
             Point3D bottomDitchDikeSide = new Point3D(1.0, 4.3, 6.4);
+            var points = new[]
+            {
+                new Point3D(1.0, 4.3, 6.4),
+                new Point3D(2.7, 2.0, 6.0)
+            };
 
+            var surfaceLine = new RingtoetsPipingSurfaceLine();
+            surfaceLine.SetGeometry(points);
+            surfaceLine.SetBottomDitchDikeSideAt(bottomDitchDikeSide);
+
             // Call
-            ChartData data = PipingChartDataFactory.CreateBottomDitchDikeSide(bottomDitchDikeSide);
+            ChartData data = PipingChartDataFactory.CreateBottomDitchDikeSide(surfaceLine);
 
             // Assert
             Assert.IsInstanceOf<ChartPointData>(data);
             ChartPointData chartPointData = (ChartPointData)data;
             Assert.AreEqual(1, chartPointData.Points.Count());
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_BottomDitchDikeSide, chartPointData.Name);
 
-            AssertEqualPointCollections(new[] { new Point2D(bottomDitchDikeSide.X, bottomDitchDikeSide.Z) }, chartPointData.Points);
+            AssertEqualLocalPointCollection(bottomDitchDikeSide, surfaceLine, chartPointData.Points);
 
             AssertEqualStyle(chartPointData.Style, Color.Green, 8, Color.Transparent, 0, ChartPointSymbol.Circle);
         }
@@ -269,25 +296,34 @@
 
             // Assert 
             var exception = Assert.Throws<ArgumentNullException>(call);
-            Assert.AreEqual("ditchDikeSide", exception.ParamName);
+            Assert.AreEqual("surfaceLine", exception.ParamName);
         }
 
         [Test]
         public void CreateDitchDikeSide_GivenDitchDikeSide_ReturnsChartDataWithDefaultStyling()
         {
             // Setup
             Point3D ditchDikeSide = new Point3D(1.0, 4.3, 6.4);
+            var points = new[]
+            {
+                new Point3D(1.0, 4.3, 6.4),
+                new Point3D(2.7, 2.0, 6.0)
+            };
 
+            var surfaceLine = new RingtoetsPipingSurfaceLine();
+            surfaceLine.SetGeometry(points);
+            surfaceLine.SetDitchDikeSideAt(ditchDikeSide);
+
             // Call
-            ChartData data = PipingChartDataFactory.CreateDitchDikeSide(ditchDikeSide);
+            ChartData data = PipingChartDataFactory.CreateDitchDikeSide(surfaceLine);
 
             // Assert
             Assert.IsInstanceOf<ChartPointData>(data);
             ChartPointData chartPointData = (ChartPointData)data;
             Assert.AreEqual(1, chartPointData.Points.Count());
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DitchDikeSide, chartPointData.Name);
 
-            AssertEqualPointCollections(new[] { new Point2D(ditchDikeSide.X, ditchDikeSide.Z) }, chartPointData.Points);
+            AssertEqualLocalPointCollection(ditchDikeSide, surfaceLine, chartPointData.Points);
 
             AssertEqualStyle(chartPointData.Style, Color.Purple, 8, Color.Transparent, 0, ChartPointSymbol.Circle);
         }
@@ -300,25 +336,34 @@
 
             // Assert 
             var exception = Assert.Throws<ArgumentNullException>(call);
-            Assert.AreEqual("dikeToeAtRiver", exception.ParamName);
+            Assert.AreEqual("surfaceLine", exception.ParamName);
         }
 
         [Test]
         public void CreateDikeToeAtRiver_GivenDikeToeAtRivere_ReturnsChartDataWithDefaultStyling()
         {
             // Setup
-            Point3D dikeToeAtRiver = new Point3D(1.0, 4.3, 6.4);
+            Point3D dikeToeAtRiver = new Point3D(1.2, 2.3, 4.0);
+            var points = new[]
+            {
+                new Point3D(1.2, 2.3, 4.0),
+                new Point3D(2.7, 2.0, 6.0)
+            };
 
+            var surfaceLine = new RingtoetsPipingSurfaceLine();
+            surfaceLine.SetGeometry(points);
+            surfaceLine.SetDikeToeAtRiverAt(dikeToeAtRiver);
+
             // Call
-            ChartData data = PipingChartDataFactory.CreateDikeToeAtRiver(dikeToeAtRiver);
+            ChartData data = PipingChartDataFactory.CreateDikeToeAtRiver(surfaceLine);
 
             // Assert
             Assert.IsInstanceOf<ChartPointData>(data);
             ChartPointData chartPointData = (ChartPointData)data;
             Assert.AreEqual(1, chartPointData.Points.Count());
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DikeToeAtRiver, chartPointData.Name);
 
-            AssertEqualPointCollections(new[] { new Point2D(dikeToeAtRiver.X, dikeToeAtRiver.Z) }, chartPointData.Points);
+            AssertEqualLocalPointCollection(dikeToeAtRiver, surfaceLine, chartPointData.Points);
 
             AssertEqualStyle(chartPointData.Style, Color.Orange, 8, Color.Transparent, 0, ChartPointSymbol.Circle);
         }
@@ -331,25 +376,34 @@
 
             // Assert 
             var exception = Assert.Throws<ArgumentNullException>(call);
-            Assert.AreEqual("dikeToeAtPolder", exception.ParamName);
+            Assert.AreEqual("surfaceLine", exception.ParamName);
         }
 
         [Test]
         public void CreateDikeToeAtPolder_GivenDikeToeAtPolder_ReturnsChartDataWithDefaultStyling()
         {
             // Setup
             Point3D dikeToeAtPolder = new Point3D(1.0, 4.3, 6.4);
+            var points = new[]
+            {
+                new Point3D(1.0, 4.3, 6.4),
+                new Point3D(2.7, 2.0, 6.0)
+            };
 
+            var surfaceLine = new RingtoetsPipingSurfaceLine();
+            surfaceLine.SetGeometry(points);
+            surfaceLine.SetDikeToeAtPolderAt(dikeToeAtPolder);
+
             // Call
-            ChartData data = PipingChartDataFactory.CreateDikeToeAtPolder(dikeToeAtPolder);
+            ChartData data = PipingChartDataFactory.CreateDikeToeAtPolder(surfaceLine);
 
             // Assert
             Assert.IsInstanceOf<ChartPointData>(data);
             ChartPointData chartPointData = (ChartPointData)data;
             Assert.AreEqual(1, chartPointData.Points.Count());
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DikeToeAtPolder, chartPointData.Name);
 
-            AssertEqualPointCollections(new[] { new Point2D(dikeToeAtPolder.X, dikeToeAtPolder.Z) }, chartPointData.Points);
+            AssertEqualLocalPointCollection(dikeToeAtPolder, surfaceLine, chartPointData.Points);
 
             AssertEqualStyle(chartPointData.Style, Color.Silver, 8, Color.Transparent, 0, ChartPointSymbol.Circle);
         }
@@ -359,6 +413,16 @@
             CollectionAssert.AreEqual(points.Select(p => new Point2D(p.X, p.Y)), chartPoints);
         }
 
+        private void AssertEqualLocalPointCollection(Point3D point, RingtoetsPipingSurfaceLine surfaceLine, IEnumerable<Point2D> chartPoints)
+        {
+            Point3D first = surfaceLine.Points.First();
+            Point3D last = surfaceLine.Points.Last();
+            Point2D firstPoint = new Point2D(first.X, first.Y);
+            Point2D lastPoint = new Point2D(last.X, last.Y);
+
+            AssertEqualPointCollections(new[] { point.ProjectIntoLocalCoordinates(firstPoint, lastPoint) }, chartPoints);
+        }
+
         private void AssertEqualStyle(ChartLineStyle lineStyle, Color color, int width, DashStyle style)
         {
             Assert.AreEqual(color, lineStyle.Color);
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingInputViewTest.cs
===================================================================
diff -u -r02b8ab97baeb969e7e4008124fe05ffd944e2142 -r27e5d9fb2ffd87ea219ecfb4217a8080f819df62
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingInputViewTest.cs	(.../PipingInputViewTest.cs)	(revision 02b8ab97baeb969e7e4008124fe05ffd944e2142)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/Views/PipingInputViewTest.cs	(.../PipingInputViewTest.cs)	(revision 27e5d9fb2ffd87ea219ecfb4217a8080f819df62)
@@ -568,14 +568,14 @@
             }
         }
 
-        private const int ditchPolderSideIndex = 0;
-        private const int bottomDitchPolderSideIndex = 1;
-        private const int bottomDitchDikeSideIndex = 2;
-        private const int ditchDikeSideIndex = 3;
-        private const int dikeToeAtRiverIndex = 4;
-        private const int dikeToeAtPolderIndex = 5;
-        private const int entryPointIndex = 6;
-        private const int surfaceLineIndex = 7;        
+        private const int surfaceLineIndex = 0;
+        private const int ditchPolderSideIndex = 1;
+        private const int bottomDitchPolderSideIndex = 2;
+        private const int bottomDitchDikeSideIndex = 3;
+        private const int ditchDikeSideIndex = 4;
+        private const int dikeToeAtRiverIndex = 5;
+        private const int dikeToeAtPolderIndex = 6;
+        private const int entryPointIndex = 7;
 
         private void AssertSurfaceLineChartData(RingtoetsPipingSurfaceLine surfaceLine, ChartData chartData)
         {
@@ -600,40 +600,40 @@
 
         private void AssertCharacteristicPoints(RingtoetsPipingSurfaceLine surfaceLine, IList<ChartData> characteristicPoints)
         {
+            Point3D first = surfaceLine.Points.First();
+            Point3D last = surfaceLine.Points.Last();
+            Point2D firstPoint = new Point2D(first.X, first.Y);
+            Point2D lastPoint = new Point2D(last.X, last.Y);
+
             var ditchDikeSideData = (ChartPointData)characteristicPoints[ditchDikeSideIndex];
             Assert.AreEqual(1, ditchDikeSideData.Points.Count());
-            CollectionAssert.AreEqual(new[] { Get2DPoint(surfaceLine.DitchDikeSide) }, ditchDikeSideData.Points);
+            CollectionAssert.AreEqual(new[] { surfaceLine.DitchDikeSide.ProjectIntoLocalCoordinates(firstPoint, lastPoint) }, ditchDikeSideData.Points);
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DitchDikeSide, ditchDikeSideData.Name);
 
             var bottomDitchDikeSideData = (ChartPointData)characteristicPoints[bottomDitchDikeSideIndex];
             Assert.AreEqual(1, bottomDitchDikeSideData.Points.Count());
-            CollectionAssert.AreEqual(new[] { Get2DPoint(surfaceLine.BottomDitchDikeSide) }, bottomDitchDikeSideData.Points);
+            CollectionAssert.AreEqual(new[] { surfaceLine.BottomDitchDikeSide.ProjectIntoLocalCoordinates(firstPoint, lastPoint) }, bottomDitchDikeSideData.Points);
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_BottomDitchDikeSide, bottomDitchDikeSideData.Name);
 
             var ditchPolderSideData = (ChartPointData)characteristicPoints[ditchPolderSideIndex];
             Assert.AreEqual(1, ditchPolderSideData.Points.Count());
-            CollectionAssert.AreEqual(new[] { Get2DPoint(surfaceLine.DitchPolderSide) }, ditchPolderSideData.Points);
+            CollectionAssert.AreEqual(new[] { surfaceLine.DitchPolderSide.ProjectIntoLocalCoordinates(firstPoint, lastPoint) }, ditchPolderSideData.Points);
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DitchPolderSide, ditchPolderSideData.Name);
 
             var bottomDitchPolderSideData = (ChartPointData)characteristicPoints[bottomDitchPolderSideIndex];
             Assert.AreEqual(1, bottomDitchPolderSideData.Points.Count());
-            CollectionAssert.AreEqual(new[] { Get2DPoint(surfaceLine.BottomDitchPolderSide) }, bottomDitchPolderSideData.Points);
+            CollectionAssert.AreEqual(new[] { surfaceLine.BottomDitchPolderSide.ProjectIntoLocalCoordinates(firstPoint, lastPoint) }, bottomDitchPolderSideData.Points);
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_BottomDitchPolderSide, bottomDitchPolderSideData.Name);
 
             var dikeToeAtPolderData = (ChartPointData)characteristicPoints[dikeToeAtPolderIndex];
             Assert.AreEqual(1, dikeToeAtPolderData.Points.Count());
-            CollectionAssert.AreEqual(new[] { Get2DPoint(surfaceLine.DikeToeAtPolder) }, dikeToeAtPolderData.Points);
+            CollectionAssert.AreEqual(new[] { surfaceLine.DikeToeAtPolder.ProjectIntoLocalCoordinates(firstPoint, lastPoint) }, dikeToeAtPolderData.Points);
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DikeToeAtPolder, dikeToeAtPolderData.Name);
 
             var dikeToeAtRiverData = (ChartPointData)characteristicPoints[dikeToeAtRiverIndex];
             Assert.AreEqual(1, dikeToeAtRiverData.Points.Count());
-            CollectionAssert.AreEqual(new[] { Get2DPoint(surfaceLine.DikeToeAtRiver) }, dikeToeAtRiverData.Points);
+            CollectionAssert.AreEqual(new[] { surfaceLine.DikeToeAtRiver.ProjectIntoLocalCoordinates(firstPoint, lastPoint) }, dikeToeAtRiverData.Points);
             Assert.AreEqual(PipingDataResources.CharacteristicPoint_DikeToeAtRiver, dikeToeAtRiverData.Name);
         }
-
-        private Point2D Get2DPoint(Point3D point3D)
-        {
-            return new Point2D(point3D.X, point3D.Z);
-        }
     }
 }
\ No newline at end of file