Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SurfaceLine2Extensions.cs
===================================================================
diff -u -r877 -r951
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SurfaceLine2Extensions.cs	(.../SurfaceLine2Extensions.cs)	(revision 877)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SurfaceLine2Extensions.cs	(.../SurfaceLine2Extensions.cs)	(revision 951)
@@ -163,20 +163,18 @@
 
             bool movedPointToMatch = false;
             bool addPoint = false;
-            Point2D point = null;
-            var newPoint = new Point2D()
+            GeometryPoint point = null;
+            var newPoint = new GeometryPoint()
             {
                 X = x,
                 Z = z
             };
-            GeometryPoint gp = null;
             if (type.HasValue)
             {
                 // Get point of this type..
-                gp = line.CharacteristicPoints.GetGeometryPoint(type.Value);
-                if (gp != null)
+                point = line.CharacteristicPoints.GetGeometryPoint(type.Value);
+                if (point != null)
                 {
-                    point = new Point2D(gp.X, gp.Z);
                     // Characteristic point annotation set, check location...
                     if (point.LocationEquals(newPoint))
                     {
@@ -186,11 +184,11 @@
                     else
                     {
                         bool isAssignedToOtherCharacteristicPoints =
-                            line.GetCharacteristicPoints(gp).Count(cpt => cpt != CharacteristicPointType.None) > 1;
+                            line.GetCharacteristicPoints(point).Count(cpt => cpt != CharacteristicPointType.None) > 1;
                         if (isAssignedToOtherCharacteristicPoints)
                         {
                             // Other characteristic points exist with the same coordinates so add as new point
-                            point = line.Geometry.GetPointAt(newPoint.X, newPoint.Z); // Get point at specified coords
+                            point = line.Geometry.GetGeometryPointAt(newPoint.X, newPoint.Z); // Get point at specified coords
                             if (point == null)
                             {
                                 point = newPoint;
@@ -204,18 +202,16 @@
                             point.Z = z;
                             movedPointToMatch = true;
                         }
-                        gp.X = point.X;
-                        gp.Z = point.Z;
                     }
                 }
             }
             if (point == null)
             {
-                point = line.Geometry.GetPointAt(x, z); // Get point at specified coords
+                point = line.Geometry.GetGeometryPointAt(x, z); // Get point at specified coords
             }
             if (point == null)
             {
-                point = new Point2D()
+                point = new GeometryPoint()
                 {
                     X = x,
                     Z = z
@@ -224,23 +220,22 @@
             }
             if (addPoint)
             {
-                var newgp = new GeometryPoint(point.X, point.Z);
-                line.Geometry.Points.Add(newgp);
-                line.AddCharacteristicPoint(newgp, type ?? CharacteristicPointType.None);
+                line.Geometry.Points.Add(point);
+                line.AddCharacteristicPoint(point, type ?? CharacteristicPointType.None);
             }
             else if (type.HasValue && !movedPointToMatch)
             {
-                if (line.CharacteristicPoints.Any(cp => ReferenceEquals(cp.GeometryPoint, gp) &&
+                if (line.CharacteristicPoints.Any(cp => ReferenceEquals(cp.GeometryPoint, point) &&
                                                         cp.CharacteristicPointType != CharacteristicPointType.None))
                 {
-                    line.AddCharacteristicPoint(gp, type.Value);
+                    line.AddCharacteristicPoint(point, type.Value);
                 }
                 else
                 {
                     int index = -1;
                     for (int i = 0; i < line.CharacteristicPoints.Count; i++)
                     {
-                        if (ReferenceEquals(line.CharacteristicPoints[i].GeometryPoint, gp))
+                        if (ReferenceEquals(line.CharacteristicPoints[i].GeometryPoint, point))
                         {
                             index = i;
                             break;
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/DikesDesign/SurfaceLineAdapterTest.cs
===================================================================
diff -u
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/DikesDesign/SurfaceLineAdapterTest.cs	(revision 0)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/DikesDesign/SurfaceLineAdapterTest.cs	(revision 951)
@@ -0,0 +1,142 @@
+// Copyright (C) Stichting Deltares 2018. All rights reserved.
+//
+// This file is part of the Dam Engine.
+//
+// The Dam Engine is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero 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 Deltares.DamEngine.Calculators.Dikes_Design;
+using Deltares.DamEngine.Data.General;
+using Deltares.DamEngine.Data.Geometry;
+using Deltares.DamEngine.Data.Geotechnics;
+using NUnit.Framework;
+
+namespace Deltares.DamEngine.Calculators.Tests.DikesDesign
+{
+    [TestFixture]
+    public class SurfaceLineAdapterTest
+    {
+        private readonly Location location = new Location();
+
+        [TestFixtureTearDown]
+        public void TestFixtureTearDown()
+        {
+        }
+
+        [Test]
+        [ExpectedException(typeof(ArgumentNullException))]
+        public void ThrowsAnExceptionWhenSurfaceLineIsNull()
+        {
+            new StubSurfaceLineAdapter(null, location);
+        }
+
+        [Test]
+        [ExpectedException(typeof(SurfaceLineAdapterException))]
+        public void ThrowsAnExceptionWhenSurfaceLineHasNoDike()
+        {
+            var surfaceLine = new SurfaceLine2
+            {
+                CharacteristicPoints =
+                {
+                    GeometryMustContainPoint = true
+                },
+                Geometry = new GeometryPointString()
+            };
+            surfaceLine.EnsurePoint(0, 0);
+            surfaceLine.EnsurePoint(1, 0);
+            surfaceLine.EnsurePoint(2, 0);
+            surfaceLine.EnsurePoint(3, 0);
+            new StubSurfaceLineAdapter(surfaceLine, location);
+        }
+
+        [Test]
+        [ExpectedException(typeof(SurfaceLineAdapterException))]
+        public void ThrowsAnExceptionWhenSurfaceLineDoesNotComplyToSpecificationUsingZeroCoordValues()
+        {
+            var surfaceLine1 = new SurfaceLine2
+            {
+                CharacteristicPoints =
+                {
+                    GeometryMustContainPoint = true
+                },
+                Geometry = new GeometryPointString()
+            };
+            surfaceLine1.EnsurePointOfType(0, 0, CharacteristicPointType.DikeToeAtRiver);
+            surfaceLine1.EnsurePointOfType(0, 0, CharacteristicPointType.DikeTopAtRiver);
+            surfaceLine1.EnsurePointOfType(0, 0, CharacteristicPointType.DikeTopAtPolder);
+            surfaceLine1.EnsurePointOfType(0, 0, CharacteristicPointType.DikeToeAtPolder);
+            new StubSurfaceLineAdapter(surfaceLine1, location);
+        }
+
+        [Test]
+        [ExpectedException(typeof(SurfaceLineAdapterException))]
+        public void ThrowsAnExceptionWhenSurfaceLineDoesNotComplyToSpecificationUsingAskewDikeTop()
+        {
+            var surfaceLine1 = new SurfaceLine2
+            {
+                CharacteristicPoints =
+                {
+                    GeometryMustContainPoint = true
+                },
+                Geometry = new GeometryPointString()
+            };
+            var p1 = new GeometryPoint();
+            var p2 = new GeometryPoint() { X = 10, Z = 10 };
+            var p3 = new GeometryPoint() { X = 15, Z = 15 };
+            surfaceLine1.EnsurePointOfType(p1.X, p1.Z, CharacteristicPointType.DikeToeAtRiver);
+            surfaceLine1.EnsurePointOfType(p2.X, p2.Z, CharacteristicPointType.DikeTopAtRiver);
+            surfaceLine1.EnsurePointOfType(p3.X, p3.Z, CharacteristicPointType.DikeTopAtPolder);
+            surfaceLine1.EnsurePointOfType(p1.X, p1.Z, CharacteristicPointType.DikeToeAtPolder);
+            new StubSurfaceLineAdapter(surfaceLine1, location);
+        }
+
+        [Test]
+        [ExpectedException(typeof(SurfaceLineAdapterException))]
+        public void ThrowsAnExceptionWhenSurfaceLineDoesNotComplyToSpecificationUsingAskewTopShoulderInside()
+        {
+            var surfaceLine1 = new SurfaceLine2
+            {
+                CharacteristicPoints =
+                {
+                    GeometryMustContainPoint = true
+                },
+                Geometry = new GeometryPointString()
+            };
+            var p1 = new GeometryPoint();
+            var p2 = new GeometryPoint() { X = 10, Z = 10 };
+            var p3 = new GeometryPoint() { X = 15, Z = 10 };
+            var p4 = new GeometryPoint() { X = 17, Z = 8 };
+            var p5 = new GeometryPoint() { X = 18, Z = 9 };
+            surfaceLine1.EnsurePointOfType(p1.X, p1.Z, CharacteristicPointType.DikeToeAtRiver);
+            surfaceLine1.EnsurePointOfType(p2.X, p2.Z, CharacteristicPointType.DikeTopAtRiver);
+            surfaceLine1.EnsurePointOfType(p3.X, p3.Z, CharacteristicPointType.DikeTopAtPolder);
+            surfaceLine1.EnsurePointOfType(p4.X, p4.Z, CharacteristicPointType.ShoulderBaseInside);
+            surfaceLine1.EnsurePointOfType(p5.X, p5.Z, CharacteristicPointType.ShoulderTopInside);
+            surfaceLine1.EnsurePointOfType(p1.X, p1.Z, CharacteristicPointType.DikeToeAtPolder);
+            new StubSurfaceLineAdapter(surfaceLine1, location);
+        }
+
+        class StubSurfaceLineAdapter : SurfaceLineAdapter
+        {
+            public StubSurfaceLineAdapter(SurfaceLine2 surfaceLine, Location location)
+                : base(surfaceLine, location)
+            {
+            }
+        }
+    }
+}
Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryPointString.cs
===================================================================
diff -u -r877 -r951
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryPointString.cs	(.../GeometryPointString.cs)	(revision 877)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryPointString.cs	(.../GeometryPointString.cs)	(revision 951)
@@ -436,7 +436,7 @@
         }
 
         /// <summary>
-        /// Gets the point at.
+        /// Gets the Point2D at the specified coordinates.
         /// </summary>
         /// <param name="x">The x.</param>
         /// <param name="z">The z.</param>
@@ -448,6 +448,19 @@
                          point.Z.AlmostEquals(z, GeometryPoint.Precision));
         }
 
+        /// <summary>
+        /// Gets the GeometryPoint at the specified coordinates.
+        /// </summary>
+        /// <param name="x">The x.</param>
+        /// <param name="z">The z.</param>
+        /// <returns></returns>
+        public GeometryPoint GetGeometryPointAt(double x, double z)
+        {
+            return Points.FirstOrDefault(
+                point => point.X.AlmostEquals(x, GeometryPoint.Precision) &&
+                         point.Z.AlmostEquals(z, GeometryPoint.Precision));
+        }
+
         //#Bka: this should never be 1 method! Split it into 2 methods
         // It is used for sliplanes only and therefor uses Points instead of calcPoints
         /// <summary>
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/Deltares.DamEngine.Calculators.Tests.csproj
===================================================================
diff -u -r946 -r951
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/Deltares.DamEngine.Calculators.Tests.csproj	(.../Deltares.DamEngine.Calculators.Tests.csproj)	(revision 946)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/Deltares.DamEngine.Calculators.Tests.csproj	(.../Deltares.DamEngine.Calculators.Tests.csproj)	(revision 951)
@@ -45,6 +45,7 @@
     <Reference Include="System.Xml.Linq" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="DikesDesign\SurfaceLineAdapterTest.cs" />
     <Compile Include="KernelWrappers\Common\DamPipingHelperTests.cs" />
     <Compile Include="KernelWrappers\Common\PlLinesHelperTests.cs" />
     <Compile Include="KernelWrappers\DamMacroStabilityCommon\DamMacroStabilityTestHelper.cs" />
@@ -101,9 +102,7 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
   </ItemGroup>
-  <ItemGroup>
-    <Folder Include="DikesDesign\" />
-  </ItemGroup>
+  <ItemGroup />
   <Import Project="$(SolutionDir)..\build\Deltares.DamEngine.Version.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.