Version 4.12. Revised projections

MapProjections/Shared/WebMercatorProjection.cs

@@ -0,0 +1,33 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2018 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+#if !WINDOWS_UWP
+using System.Windows;
+#endif
+using ProjNet.CoordinateSystems;
+
+namespace MapControl.Projections
+{
+    /// <summary>
+    /// Spherical Mercator Projection implemented by setting the CoordinateSystem property of a GeoApiProjection.
+    /// See "Map Projections - A Working Manual" (https://pubs.usgs.gov/pp/1395/report.pdf), p.41-44.
+    /// </summary>
+    public class WebMercatorProjection : GeoApiProjection
+    {
+        public WebMercatorProjection()
+        {
+            IsWebMercator = true;
+            IsNormalCylindrical = true;
+            CoordinateSystem = ProjectedCoordinateSystem.WebMercator;
+        }
+
+        public override Vector GetMapScale(Location location)
+        {
+            var k = 1d / Math.Cos(location.Latitude * Math.PI / 180d); // p.44 (7-3)
+
+            return new Vector(ViewportScale * k, ViewportScale * k);
+        }
+    }
+}