Index: Ringtoets/Common/src/Ringtoets.Common.Utils/TypeConverters/BackgroundDataConverter.cs
===================================================================
diff -u -r935e492135a782b9e63c0924df798ebb358ac7cc -ra7c7037989d2ccfa2d482a1f54f7f9f8bac0b9e7
--- Ringtoets/Common/src/Ringtoets.Common.Utils/TypeConverters/BackgroundDataConverter.cs	(.../BackgroundDataConverter.cs)	(revision 935e492135a782b9e63c0924df798ebb358ac7cc)
+++ Ringtoets/Common/src/Ringtoets.Common.Utils/TypeConverters/BackgroundDataConverter.cs	(.../BackgroundDataConverter.cs)	(revision a7c7037989d2ccfa2d482a1f54f7f9f8bac0b9e7)
@@ -68,32 +68,45 @@
         /// <exception cref="InvalidEnumArgumentException">Thrown when
         /// <see cref="WellKnownBackgroundDataConfiguration.WellKnownTileSource"/> contains an 
         /// invalid value for <see cref="WellKnownTileSource"/>.</exception>
+        /// <exception cref="NotSupportedException">Thrown when <see cref="BackgroundData.Configuration"/>
+        /// doesn't is of a type that can be converted.</exception>
         public static ImageBasedMapData ConvertFrom(BackgroundData backgroundData)
         {
             if (backgroundData == null)
             {
                 throw new ArgumentNullException(nameof(backgroundData));
             }
 
-            ImageBasedMapData mapData = null;
+            ImageBasedMapData mapData = CreateMapData(backgroundData);
 
+            mapData.Name = backgroundData.Name;
+            mapData.IsVisible = backgroundData.IsVisible;
+            mapData.Transparency = backgroundData.Transparency;
+
+            return mapData;
+        }
+
+        /// <summary>
+        /// Creates the map data with data of the <see cref="IBackgroundDataConfiguration"/>.
+        /// </summary>
+        /// <param name="backgroundData">The background data to get the configuration from
+        /// and create the data for.</param>
+        /// <returns>The created <see cref="ImageBasedMapData"/>.</returns>
+        /// <exception cref="NotSupportedException">Thrown when <see cref="BackgroundData.Configuration"/>
+        /// doesn't is of a type that can be converted.</exception>
+        private static ImageBasedMapData CreateMapData(BackgroundData backgroundData)
+        {
             var wmtsBackgroundDataConfiguration = backgroundData.Configuration as WmtsBackgroundDataConfiguration;
             if (wmtsBackgroundDataConfiguration != null)
             {
-                mapData = CreateWmtsMapData(wmtsBackgroundDataConfiguration);
+                return CreateWmtsMapData(wmtsBackgroundDataConfiguration);
             }
-
             var wellKnownBackgroundDataConfiguration = backgroundData.Configuration as WellKnownBackgroundDataConfiguration;
             if (wellKnownBackgroundDataConfiguration != null)
             {
-                mapData = CreateWellKnownMapdata(wellKnownBackgroundDataConfiguration);
+                return CreateWellKnownMapdata(wellKnownBackgroundDataConfiguration);
             }
-
-            mapData.Name = backgroundData.Name;
-            mapData.IsVisible = backgroundData.IsVisible;
-            mapData.Transparency = backgroundData.Transparency;
-
-            return mapData;
+            throw new NotSupportedException($"Can't create a image based map data for {backgroundData.Configuration.GetType()}.");
         }
 
         /// <summary>
Index: Ringtoets/Common/test/Ringtoets.Common.Utils.Test/TypeConverters/BackgroundDataConverterTest.cs
===================================================================
diff -u -r935e492135a782b9e63c0924df798ebb358ac7cc -ra7c7037989d2ccfa2d482a1f54f7f9f8bac0b9e7
--- Ringtoets/Common/test/Ringtoets.Common.Utils.Test/TypeConverters/BackgroundDataConverterTest.cs	(.../BackgroundDataConverterTest.cs)	(revision 935e492135a782b9e63c0924df798ebb358ac7cc)
+++ Ringtoets/Common/test/Ringtoets.Common.Utils.Test/TypeConverters/BackgroundDataConverterTest.cs	(.../BackgroundDataConverterTest.cs)	(revision a7c7037989d2ccfa2d482a1f54f7f9f8bac0b9e7)
@@ -34,7 +34,7 @@
 namespace Ringtoets.Common.Utils.Test.TypeConverters
 {
     [TestFixture]
-    public class BackgroundDataConverterTest
+    public class BackgroundDataConverterTestW
     {
         private static IEnumerable<TestCaseData> WmtsMapDatas
         {
@@ -69,7 +69,7 @@
 
             // Assert
             var exception = Assert.Throws<NotSupportedException>(call);
-            string expectedMessage = $"Can't create a background data configuration for {unsupportedImageBasedMapData.GetType()}.";
+            string expectedMessage = $"Can't create a background data configuration for {typeof(TestImageBasedMapData)}.";
             Assert.AreEqual(expectedMessage, exception.Message);
         }
 
@@ -130,6 +130,21 @@
         }
 
         [Test]
+        public void ConvertFrom_ConfigurationTypeNotSupportedForConversion_ThrowNotSupportedException()
+        {
+            // Setup
+            var backgroundData = new BackgroundData(new TestBackgroundDataConfiguration());
+
+            // Call
+            TestDelegate test = () => BackgroundDataConverter.ConvertFrom(backgroundData);
+
+            // Assert
+            var exception = Assert.Throws<NotSupportedException>(test);
+            string expectedMessage = $"Can't create a image based map data for {typeof(TestBackgroundDataConfiguration)}.";
+            Assert.AreEqual(expectedMessage, exception.Message);
+        }
+
+        [Test]
         [TestCaseSource(nameof(WmtsMapDatas))]
         public void ConvertFrom_BackgroundData_ReturnWmtsMapData(WmtsMapData mapData)
         {