Index: DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data.Tests/Deltares.Dam.Data.Tests.csproj
===================================================================
diff -u -r6436 -r6554
--- DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data.Tests/Deltares.Dam.Data.Tests.csproj	(.../Deltares.Dam.Data.Tests.csproj)	(revision 6436)
+++ DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data.Tests/Deltares.Dam.Data.Tests.csproj	(.../Deltares.Dam.Data.Tests.csproj)	(revision 6554)
@@ -4,6 +4,12 @@
         <ProjectReference Include="..\Deltares.Dam.Data\Deltares.Dam.Data.csproj"/>
     </ItemGroup>
     <ItemGroup>
+        <Reference Include="Deltares.Geometry">
+          <HintPath>..\..\..\lib\DSL-Geo\Deltares.Geometry.dll</HintPath>
+        </Reference>
+        <Reference Include="Deltares.Geotechnics">
+          <HintPath>..\..\..\lib\DSL-Geo\Deltares.Geotechnics.dll</HintPath>
+        </Reference>
         <Reference Include="Deltares.Standard">
             <HintPath>..\..\..\lib\DSL-Core\Deltares.Standard.dll</HintPath>
         </Reference>
Index: DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data/Translations.xml
===================================================================
diff -u -r6439 -r6554
--- DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data/Translations.xml	(.../Translations.xml)	(revision 6439)
+++ DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data/Translations.xml	(.../Translations.xml)	(revision 6554)
@@ -840,4 +840,7 @@
     <Translation ID="CanNotReadOldFile" 
                  en-US="You try to open an old file. That is not possible. Please make a new damx file based upon a defx file."
                  nl-NL="U probeert een oud bestand te openen, dat is niet mogelijk. Maak een nieuw damx bestand op basis van een defx bestand."/>
+    <Translation ID="NotAllRequiredCharacteristicPointsAreDefined"
+                 en-US="Not all the required characteristic points (see user manual) are available in the surface line."
+                 nl-NL="Niet alle verplichte karakteristieke punten (zie handleiding) zijn aanwezig in de hoogtegeometrie."/>
 </Translations>
\ No newline at end of file
Index: DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data.Tests/LocationTests.cs
===================================================================
diff -u
--- DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data.Tests/LocationTests.cs	(revision 0)
+++ DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data.Tests/LocationTests.cs	(revision 6554)
@@ -0,0 +1,122 @@
+// Copyright (C) Stichting Deltares 2025. All rights reserved.
+// 
+// This file is part of the application DAM - UI.
+// 
+// DAM - UI is free software: you can redistribute it and/or modify
+// it under the terms of the GNU 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 General Public License for more details.
+// 
+// You should have received a copy of the GNU 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 Deltares.Geometry;
+using Deltares.Geotechnics.GeotechnicalGeometry;
+using Deltares.Geotechnics.SurfaceLines;
+using Deltares.Standard.Validation;
+using NUnit.Framework;
+
+namespace Deltares.Dam.Data.Tests;
+
+[TestFixture]
+public class LocationTests
+{
+    [Test]
+    [TestCase(CharacteristicPointType.InsertRiverChannel, true)]
+    [TestCase(CharacteristicPointType.SurfaceLevelOutside, false)]
+    [TestCase(CharacteristicPointType.DikeToeAtRiver, false)]
+    [TestCase(CharacteristicPointType.DikeTopAtRiver, false)]
+    [TestCase(CharacteristicPointType.DikeTopAtPolder, false)]
+    [TestCase(CharacteristicPointType.DikeToeAtPolder, false)]
+    [TestCase(CharacteristicPointType.SurfaceLevelInside, false)]
+    public void GivenSurfaceLine_WhenValidatingTheRequiredCharacteristicPoints_ReturnsExpectedResult(CharacteristicPointType typeNotPresent, bool isValid)
+    {
+        SurfaceLine2 surfaceLine = CreateSurfaceLine(typeNotPresent);
+        var location = new Location();
+        location.LocalXZSurfaceLine2 = surfaceLine;
+
+        ValidationResult[] validationResults = location.ValidateRequiredCharacteristicPoints();
+
+        if (isValid)
+        {
+            Assert.That(validationResults, Is.Null);
+        }
+        else
+        {
+            Assert.That(validationResults, Has.Length.EqualTo(1));
+            Assert.Multiple(() =>
+            {
+                Assert.That(validationResults[0].Subject, Is.EqualTo(surfaceLine));
+                Assert.That(validationResults[0].Text, Is.EqualTo("Not all the required characteristic points (see user manual) are available in the surface line."));
+            });
+        }
+    }
+
+    private static SurfaceLine2 CreateSurfaceLine(CharacteristicPointType typeNotPresent)
+    {
+        var gp0 = new GeometryPoint(0.0, 0.0, 0.0);
+        var gp1 = new GeometryPoint(1.0, 0.0, 0.0);
+        var gp2 = new GeometryPoint(2.0, 0.0, 1.0);
+        var gp3 = new GeometryPoint(4.0, 0.0, 1.0);
+        var gp4 = new GeometryPoint(10.0, 0.0, 0.0);
+        var gp5 = new GeometryPoint(12.0, 0.0, 0.0);
+
+        var line = new LocalizedGeometryPointString();
+        line.Points.Add(gp0);
+        line.Points.Add(new GeometryPoint(0.1, 0.0, 0.0));
+        line.Points.Add(new GeometryPoint(0.9, 0.0, 0.0));
+        line.Points.Add(gp1);
+        line.Points.Add(gp2);
+        line.Points.Add(gp3);
+        line.Points.Add(new GeometryPoint(4.1, 0.0, 1.0));
+        line.Points.Add(new GeometryPoint(4.1, 0.0, 1.0));
+        line.Points.Add(gp4);
+        line.Points.Add(gp5);
+
+        var surfaceLine = new SurfaceLine2
+        {
+            Geometry = line
+        };
+
+        if (typeNotPresent != CharacteristicPointType.SurfaceLevelOutside)
+        {
+            surfaceLine.AddCharacteristicPoint(gp0, CharacteristicPointType.SurfaceLevelOutside);
+        }
+
+        if (typeNotPresent != CharacteristicPointType.DikeToeAtRiver)
+        {
+            surfaceLine.AddCharacteristicPoint(gp0, CharacteristicPointType.DikeToeAtRiver);
+        }
+
+        if (typeNotPresent != CharacteristicPointType.DikeTopAtRiver)
+        {
+            surfaceLine.AddCharacteristicPoint(gp2, CharacteristicPointType.DikeTopAtRiver);
+        }
+
+        if (typeNotPresent != CharacteristicPointType.DikeTopAtPolder)
+        {
+            surfaceLine.AddCharacteristicPoint(gp3, CharacteristicPointType.DikeTopAtPolder);
+        }
+
+        if (typeNotPresent != CharacteristicPointType.DikeToeAtPolder)
+        {
+            surfaceLine.AddCharacteristicPoint(gp4, CharacteristicPointType.DikeToeAtPolder);
+        }
+
+        if (typeNotPresent != CharacteristicPointType.SurfaceLevelInside)
+        {
+            surfaceLine.AddCharacteristicPoint(gp5, CharacteristicPointType.SurfaceLevelInside);
+        }
+
+        return surfaceLine;
+    }
+}
\ No newline at end of file
Index: DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data/Location.cs
===================================================================
diff -u -r6436 -r6554
--- DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data/Location.cs	(.../Location.cs)	(revision 6436)
+++ DamClients/DamUI/trunk/src/DamClientsLibrary/Deltares.Dam.Data/Location.cs	(.../Location.cs)	(revision 6554)
@@ -1081,6 +1081,21 @@
         return new ValidationResult[0];
     }
 
+    [Validate]
+    public ValidationResult[] ValidateRequiredCharacteristicPoints()
+    {
+        if (!AreAllRequiredCharacteristicTypesAvailable(LocalXZSurfaceLine2))
+        {
+            return new[]
+            {
+                new ValidationResult(ValidationResultType.Error, 
+                                     LocalizationManager.GetTranslatedText(this, "NotAllRequiredCharacteristicPointsAreDefined"), LocalXZSurfaceLine2)
+            };
+        }
+
+        return null;
+    }
+
     /// <summary>
     /// Gets the dike embankment soil.
     /// </summary>
@@ -1589,6 +1604,24 @@
         return "";
     }
 
+    /// <summary>
+    /// Are all required characteristic types available.
+    /// </summary>
+    /// <param name="surfaceLine">The surface line.</param>
+    /// <returns></returns>
+    private static bool AreAllRequiredCharacteristicTypesAvailable(SurfaceLine2 surfaceLine)
+    {
+        IEnumerable<CharacteristicPoint> requiredPoints =
+            surfaceLine.CharacteristicPoints.Where(p => !double.IsNaN(p.X) &&
+                                                        (p.CharacteristicPointType == CharacteristicPointType.SurfaceLevelOutside ||
+                                                         p.CharacteristicPointType == CharacteristicPointType.DikeToeAtRiver ||
+                                                         p.CharacteristicPointType == CharacteristicPointType.DikeTopAtRiver ||
+                                                         p.CharacteristicPointType == CharacteristicPointType.DikeTopAtPolder ||
+                                                         p.CharacteristicPointType == CharacteristicPointType.DikeToeAtPolder ||
+                                                         p.CharacteristicPointType == CharacteristicPointType.SurfaceLevelInside)).OrderBy(p => p.CharacteristicPointType);
+        return requiredPoints.Count() == 6;
+    }
+
     #region IGeographic Members
 
     [Label("Zone type")]