Index: Core/Components/src/Core.Components.DotSpatial/Converter/MapDataConverter.cs
===================================================================
diff -u -r2d9376748bc82f1d5e6a12f25e815cd076b1253c -rd2eecf88d4da2c824ccfa6eb81cf0a75733eccde
--- Core/Components/src/Core.Components.DotSpatial/Converter/MapDataConverter.cs	(.../MapDataConverter.cs)	(revision 2d9376748bc82f1d5e6a12f25e815cd076b1253c)
+++ Core/Components/src/Core.Components.DotSpatial/Converter/MapDataConverter.cs	(.../MapDataConverter.cs)	(revision d2eecf88d4da2c824ccfa6eb81cf0a75733eccde)
@@ -93,6 +93,7 @@
 
         /// <summary>
         /// Converts all feature related data from <paramref name="data"/> to <paramref name="layer"/>.
+        /// Any features already part of <paramref name="layer"/> are cleared.
         /// </summary>
         /// <param name="data">The data to convert the feature related data from.</param>
         /// <param name="layer">The layer to convert the feature related data to.</param>
Index: Core/Components/src/Core.Components.DotSpatial/Converter/MapLineDataConverter.cs
===================================================================
diff -u -r9fb229f4fc4fe2c11e79e344c76ceb220f2dc96a -rd2eecf88d4da2c824ccfa6eb81cf0a75733eccde
--- Core/Components/src/Core.Components.DotSpatial/Converter/MapLineDataConverter.cs	(.../MapLineDataConverter.cs)	(revision 9fb229f4fc4fe2c11e79e344c76ceb220f2dc96a)
+++ Core/Components/src/Core.Components.DotSpatial/Converter/MapLineDataConverter.cs	(.../MapLineDataConverter.cs)	(revision d2eecf88d4da2c824ccfa6eb81cf0a75733eccde)
@@ -49,6 +49,9 @@
 
         protected override void ConvertLayerFeatures(MapLineData data, MapLineLayer layer)
         {
+            layer.FeatureSet.Features.Clear();
+            layer.FeatureSet.DataTable.Clear();
+
             foreach (MapFeature mapFeature in data.Features)
             {
                 AddMetaDataAsAttributes(mapFeature, layer.FeatureSet, new Feature(GetGeometry(mapFeature), layer.FeatureSet));
Index: Core/Components/src/Core.Components.DotSpatial/Converter/MapPointDataConverter.cs
===================================================================
diff -u -r5123cc1c54afb3827d844dd312f771de5c037986 -rd2eecf88d4da2c824ccfa6eb81cf0a75733eccde
--- Core/Components/src/Core.Components.DotSpatial/Converter/MapPointDataConverter.cs	(.../MapPointDataConverter.cs)	(revision 5123cc1c54afb3827d844dd312f771de5c037986)
+++ Core/Components/src/Core.Components.DotSpatial/Converter/MapPointDataConverter.cs	(.../MapPointDataConverter.cs)	(revision d2eecf88d4da2c824ccfa6eb81cf0a75733eccde)
@@ -47,6 +47,9 @@
 
         protected override void ConvertLayerFeatures(MapPointData data, MapPointLayer layer)
         {
+            layer.FeatureSet.Features.Clear();
+            layer.FeatureSet.DataTable.Clear();
+
             foreach (var ringtoetsMapFeature in data.Features)
             {
                 foreach (var feature in GetAllMapFeatureCoordinates(ringtoetsMapFeature)
Index: Core/Components/src/Core.Components.DotSpatial/Converter/MapPolygonDataConverter.cs
===================================================================
diff -u -r9fb229f4fc4fe2c11e79e344c76ceb220f2dc96a -rd2eecf88d4da2c824ccfa6eb81cf0a75733eccde
--- Core/Components/src/Core.Components.DotSpatial/Converter/MapPolygonDataConverter.cs	(.../MapPolygonDataConverter.cs)	(revision 9fb229f4fc4fe2c11e79e344c76ceb220f2dc96a)
+++ Core/Components/src/Core.Components.DotSpatial/Converter/MapPolygonDataConverter.cs	(.../MapPolygonDataConverter.cs)	(revision d2eecf88d4da2c824ccfa6eb81cf0a75733eccde)
@@ -47,6 +47,9 @@
 
         protected override void ConvertLayerFeatures(MapPolygonData data, MapPolygonLayer layer)
         {
+            layer.FeatureSet.Features.Clear();
+            layer.FeatureSet.DataTable.Clear();
+
             foreach (var mapFeature in data.Features)
             {
                 var geometryList = new List<IPolygon>();