Added function to obtain WaterIslands from vector tile.

Runtime/VectorTile.cs

-using GluonGui.WorkspaceWindow.Views.WorkspaceExplorer.Configuration;
 using Mapbox.Vector.Tile;
 using System;
 using System.Collections.Generic;
@@ -193,6 +192,13 @@ namespace Wander
             return numFailedPolys;
         }
 
+        bool IsPolygonLayerWater( int layerIdx, int featureIdx, int waterLayerIdx )
+        {
+            var layer = layers[layerIdx];
+            var feature = layer.VectorTileFeatures[featureIdx];
+            return feature.SelectedLayerIdx==waterLayerIdx;
+        }
+
         bool DoesPolygonLayerQualify( int layerIdx, int featureIdx )
         {
             var layer = layers[layerIdx];
@@ -351,6 +357,37 @@ namespace Wander
             layersIdentified = true;
         }
 
+        public List<List<TriangulatedPolygon>> GetWaterPolygons( int waterLayerIdx, ref bool cancelToken )
+        {
+            UnityEngine.Debug.Assert( triangulated, "First call Triangulate." );
+            UnityEngine.Debug.Assert( layersIdentified, "Identify layers first." );
+
+            Stopwatch sw = new Stopwatch();
+            sw.Restart();
+
+            var waters = new List<List<TriangulatedPolygon>>();
+
+            for (int l = 0;l < polygonLayers.Count;l++)
+            {
+                var layer = layers[l];
+                var water = new List<TriangulatedPolygon>();
+                for (int f = 0;f < layer.VectorTileFeatures.Count && !cancelToken ;f++)
+                {
+                    if (DoesPolygonLayerQualify( l, f ) && IsPolygonLayerWater(l, f, waterLayerIdx))
+                    {
+                        var poly = polygonLayers[l][f];
+                        water.Add( poly );
+                    }
+                }
+                if (water.Count> 0)
+                {
+                    waters.Add( water );
+                }    
+            }
+
+            return waters;
+        }
+
         // Generates a raster for each position (pixel). 2 pixels are pushed in 1 (each 16 bit).
         // If no polygon was hit, 15 is encoded (reserved).
         // If polygon was hit, but no feature was matched, also 15 is encoded.