Version 4.8.0: Improved WPF MapPolyline and MapPolygon accuracy.

MapControl/Shared/MapBase.cs

@@ -222,7 +222,12 @@ namespace MapControl
         }
 
         /// <summary>
-        /// Gets the scaling transformation from meters to viewport coordinate units at the Center location.
+        /// Gets the transformation from cartesian map coordinates to viewport coordinates (pixels).
+        /// </summary>
+        public MatrixTransform ViewportTransform { get; } = new MatrixTransform();
+
+        /// <summary>
+        /// Gets the scaling transformation from meters to viewport coordinates at the Center location.
         /// </summary>
         public ScaleTransform ScaleTransform { get; } = new ScaleTransform();
 
@@ -708,9 +713,12 @@ namespace MapControl
                 }
             }
 
+            ViewportTransform.Matrix = projection.ViewportTransform;
+
             var scale = projection.GetMapScale(center);
             ScaleTransform.ScaleX = scale.X;
             ScaleTransform.ScaleY = scale.Y;
+
             RotateTransform.Angle = Heading;
 
             OnViewportChanged(new ViewportChangedEventArgs(projectionChanged, Center.Longitude - centerLongitude));

MapControl/Shared/MapPanel.cs

@@ -261,7 +261,7 @@ namespace MapControl
                 var center = new Point(rect.X + rect.Width / 2d, rect.Y + rect.Height / 2d);
 
                 rotation = parentMap.Heading;
-                viewportPosition = projection.ViewportTransformMatrix.Transform(center);
+                viewportPosition = projection.ViewportTransform.Transform(center);
 
                 if (parentMap.MapProjection.IsContinuous &&
                     (viewportPosition.X < 0d || viewportPosition.X > parentMap.RenderSize.Width ||

MapControl/Shared/MapPolygon.cs

@@ -0,0 +1,49 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2018 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System.Collections.Generic;
+#if WINDOWS_UWP
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Media;
+#else
+using System.ComponentModel;
+using System.Windows;
+using System.Windows.Media;
+#endif
+
+namespace MapControl
+{
+    /// <summary>
+    /// A polygon defined by a collection of Locations.
+    /// </summary>
+    public class MapPolygon : MapShape
+    {
+        public static readonly DependencyProperty LocationsProperty = DependencyProperty.Register(
+            nameof(Locations), typeof(IEnumerable<Location>), typeof(MapPolygon),
+            new PropertyMetadata(null, (o, e) => ((MapPolygon)o).DataCollectionPropertyChanged(e)));
+
+        /// <summary>
+        /// Gets or sets the Locations that define the polygon points.
+        /// </summary>
+#if !WINDOWS_UWP
+        [TypeConverter(typeof(LocationCollectionConverter))]
+#endif
+        public IEnumerable<Location> Locations
+        {
+            get { return (IEnumerable<Location>)GetValue(LocationsProperty); }
+            set { SetValue(LocationsProperty, value); }
+        }
+
+        protected override void UpdateData()
+        {
+            var figures = ((PathGeometry)Data).Figures;
+            figures.Clear();
+
+            if (ParentMap != null)
+            {
+                AddPolylineFigures(figures, Locations, true);
+            }
+        }
+    }
+}

MapControl/Shared/MapPolyline.cs

@@ -0,0 +1,49 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2018 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System.Collections.Generic;
+#if WINDOWS_UWP
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Media;
+#else
+using System.ComponentModel;
+using System.Windows;
+using System.Windows.Media;
+#endif
+
+namespace MapControl
+{
+    /// <summary>
+    /// A polyline defined by a collection of Locations.
+    /// </summary>
+    public class MapPolyline : MapShape
+    {
+        public static readonly DependencyProperty LocationsProperty = DependencyProperty.Register(
+            nameof(Locations), typeof(IEnumerable<Location>), typeof(MapPolyline),
+            new PropertyMetadata(null, (o, e) => ((MapPolyline)o).DataCollectionPropertyChanged(e)));
+
+        /// <summary>
+        /// Gets or sets the Locations that define the polyline points.
+        /// </summary>
+#if !WINDOWS_UWP
+        [TypeConverter(typeof(LocationCollectionConverter))]
+#endif
+        public IEnumerable<Location> Locations
+        {
+            get { return (IEnumerable<Location>)GetValue(LocationsProperty); }
+            set { SetValue(LocationsProperty, value); }
+        }
+
+        protected override void UpdateData()
+        {
+            var figures = ((PathGeometry)Data).Figures;
+            figures.Clear();
+
+            if (ParentMap != null)
+            {
+                AddPolylineFigures(figures, Locations, false);
+            }
+        }
+    }
+}

MapControl/Shared/MapProjection.cs

@@ -59,14 +59,9 @@ namespace MapControl
         public double MaxLatitude { get; protected set; } = 90d;
 
         /// <summary>
-        /// Gets the transformation matrix from cartesian map coordinates to viewport coordinates (pixels).
+        /// Gets the transform matrix from cartesian map coordinates to viewport coordinates (pixels).
         /// </summary>
-        public Matrix ViewportTransformMatrix { get; private set; }
-
-        /// <summary>
-        /// Gets the transformation from cartesian map coordinates to viewport coordinates (pixels).
-        /// </summary>
-        public MatrixTransform ViewportTransform { get; } = new MatrixTransform();
+        public Matrix ViewportTransform { get; private set; }
 
         /// <summary>
         /// Gets the scaling factor from cartesian map coordinates to viewport coordinates.
@@ -114,7 +109,7 @@ namespace MapControl
         /// </summary>
         public Point LocationToViewportPoint(Location location)
         {
-            return ViewportTransformMatrix.Transform(LocationToPoint(location));
+            return ViewportTransform.Transform(LocationToPoint(location));
         }
 
         /// <summary>
@@ -145,8 +140,7 @@ namespace MapControl
             var center = LocationToPoint(mapCenter);
             var matrix = CreateTransformMatrix(center, ViewportScale, -ViewportScale, heading, viewportCenter);
 
-            ViewportTransformMatrix = matrix;
-            ViewportTransform.Matrix = matrix;
+            ViewportTransform = matrix;
 
             matrix.Invert();
             inverseViewportTransformMatrix = matrix;

MapControl/Shared/MapShape.cs

@@ -35,7 +35,7 @@ namespace MapControl
         {
             if (parentMap != null)
             {
-                OnViewportChanged(parentMap, new ViewportChangedEventArgs());
+                UpdateData();
             }
         }
 
@@ -58,11 +58,17 @@ namespace MapControl
                     parentMap.ViewportChanged += OnViewportChanged;
                 }
 
-                SetDataTransform();
                 UpdateData();
             }
         }
 
+        private void OnViewportChanged(object sender, ViewportChangedEventArgs e)
+        {
+            UpdateData();
+        }
+
+        protected abstract void UpdateData();
+
         protected MapShape()
             : this(new PathGeometry())
         {
@@ -75,10 +81,6 @@ namespace MapControl
             MapPanel.InitMapElement(this);
         }
 
-        partial void SetDataTransform(); // WPF only
-
-        protected abstract void UpdateData();
-
         protected Point LocationToPoint(Location location)
         {
             var point = parentMap.MapProjection.LocationToPoint(location);
@@ -97,7 +99,7 @@ namespace MapControl
 
         protected Point LocationToViewportPoint(Location location)
         {
-            return parentMap.MapProjection.ViewportTransformMatrix.Transform(LocationToPoint(location));
+            return parentMap.MapProjection.ViewportTransform.Transform(LocationToPoint(location));
         }
 
         protected double GetLongitudeOffset()