Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Importer/CsvImporter.cs
===================================================================
diff -u -r3160 -r3176
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Importer/CsvImporter.cs	(.../CsvImporter.cs)	(revision 3160)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Importer/CsvImporter.cs	(.../CsvImporter.cs)	(revision 3176)
@@ -142,6 +142,7 @@
             List<string> errors)
         {
             const string importFile = "characteristicpoints.csv";
+            const double diff = 1e-4;
             string fullFilePath = Path.Combine(inputFolderName, importFile);
             try
             {
@@ -166,7 +167,7 @@
                     foreach (var point in characteristicPointRecord.Points)
                     {
                         // ignore 'unset' points
-                        if (!((point.X == -1) && (point.Y == -1) && (point.Z == -1)))
+                        if (!(Math.Abs(point.X + 1) < diff && Math.Abs(point.Y + 1) < diff && Math.Abs(point.Z + 1) < diff))
                         {
                             var surfaceLinePoint = surfaceLine.GetSurfaceLinePointByLocation(point.X, point.Z);
                             if (surfaceLinePoint == null)