Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/PlLinesCreator/PLLineConstructor.cs
===================================================================
diff -u -r6127 -r6180
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/PlLinesCreator/PLLineConstructor.cs	(.../PLLineConstructor.cs)	(revision 6127)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/PlLinesCreator/PLLineConstructor.cs	(.../PLLineConstructor.cs)	(revision 6180)
@@ -63,6 +63,10 @@
         Insert(new PlLinePoint(x, z));
     }
 
+    /// <summary>
+    /// Determine the Z co-ordinate of the last point of the line.
+    /// </summary>
+    /// <returns>The Z co-ordinate of the last point of the line.</returns>
     public double GetLastZ()
     {
         return line[line.Keys.Max()].Z;
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/PlLinesCreator/PlLineConstructorTests.cs
===================================================================
diff -u
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/PlLinesCreator/PlLineConstructorTests.cs	(revision 0)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/PlLinesCreator/PlLineConstructorTests.cs	(revision 6180)
@@ -0,0 +1,42 @@
+// Copyright (C) Stichting Deltares 2024. 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 Deltares.DamEngine.Calculators.PlLinesCreator;
+using NUnit.Framework;
+
+namespace Deltares.DamEngine.Calculators.Tests.PlLinesCreator;
+
+[TestFixture]
+public class PlLineConstructorTests
+{
+    [Test]
+    public void GivenAPlLine_WhenDeterminingTheZOfTheLastPoint_ExpectedValueReturned()
+    {
+        var plLineConstructor = new PlLineConstructor();
+        plLineConstructor.Insert(30, 9);
+        plLineConstructor.Insert(20, 8);
+        plLineConstructor.Insert(15, 10);
+
+        double lastZValue = plLineConstructor.GetLastZ();
+        
+        Assert.That(lastZValue, Is.EqualTo(9));
+    }
+}
\ No newline at end of file