From 2b41d298f4913097d9992149412d2cc8e431c8fc Mon Sep 17 00:00:00 2001
From: ClemensF <fischer.clemens@gmail.com>
Date: Wed, 1 Apr 2020 18:04:39 +0200
Subject: [PATCH] Version 5.0.1: Reworked MapBase and MapProjection

---
 .../Shared/EquirectangularProjection.cs       |  4 ++--
 MapControl/Shared/MapBase.cs                  | 12 ++++-------
 MapControl/Shared/MapProjection.cs            | 12 +++++------
 MapControl/Shared/ViewTransform.cs            | 20 +++++++++----------
 4 files changed, 22 insertions(+), 26 deletions(-)

diff --git a/MapControl/Shared/EquirectangularProjection.cs b/MapControl/Shared/EquirectangularProjection.cs
index ebdb3c0b..6a853388 100644
--- a/MapControl/Shared/EquirectangularProjection.cs
+++ b/MapControl/Shared/EquirectangularProjection.cs
@@ -14,7 +14,7 @@ namespace MapControl
 {
     /// <summary>
     /// Equirectangular Projection.
-    /// Longitude and Latitude values are transformed linearly to X and Y in meters.
+    /// Longitude and Latitude values are transformed linearly to X and Y values in meters.
     /// </summary>
     public class EquirectangularProjection : MapProjection
     {
@@ -47,7 +47,7 @@ namespace MapControl
         public override string GetBboxValue(Rect rect)
         {
             return string.Format(CultureInfo.InvariantCulture,
-                CrsId != "CRS:84" ? "{1},{0},{3},{2}" : "{0},{1},{2},{3}",
+                CrsId == "CRS:84" ? "{0},{1},{2},{3}" : "{1},{0},{3},{2}",
                 rect.X / UnitsPerDegree, rect.Y / UnitsPerDegree,
                 (rect.X + rect.Width) / UnitsPerDegree, (rect.Y + rect.Height) / UnitsPerDegree);
         }
diff --git a/MapControl/Shared/MapBase.cs b/MapControl/Shared/MapBase.cs
index 66b1e1d8..0d2d131a 100644
--- a/MapControl/Shared/MapBase.cs
+++ b/MapControl/Shared/MapBase.cs
@@ -692,16 +692,13 @@ namespace MapControl
 
         private void UpdateTransform(bool resetTransformCenter = false, bool projectionChanged = false)
         {
+            var viewScale = ViewTransform.ZoomLevelToScale(ZoomLevel);
+            var center = transformCenter ?? Center;
             var projection = MapProjection;
 
             projection.Center = ProjectionCenter ?? Center;
 
-            var center = transformCenter ?? Center;
-            var mapCenter = projection.LocationToMap(center);
-
-            var viewScale = ViewTransform.ZoomLevelToScale(ZoomLevel);
-
-            ViewTransform.SetTransform(mapCenter, viewCenter, viewScale, Heading);
+            ViewTransform.SetTransform(projection.LocationToMap(center), viewCenter, viewScale, Heading);
 
             if (transformCenter != null)
             {
@@ -726,9 +723,8 @@ namespace MapControl
                     ResetTransformCenter();
 
                     projection.Center = ProjectionCenter ?? center;
-                    mapCenter = projection.LocationToMap(center);
 
-                    ViewTransform.SetTransform(mapCenter, viewCenter, viewScale, Heading);
+                    ViewTransform.SetTransform(projection.LocationToMap(center), viewCenter, viewScale, Heading);
                 }
             }
 
diff --git a/MapControl/Shared/MapProjection.cs b/MapControl/Shared/MapProjection.cs
index f13fb09b..640a706f 100644
--- a/MapControl/Shared/MapProjection.cs
+++ b/MapControl/Shared/MapProjection.cs
@@ -22,15 +22,15 @@ namespace MapControl
         public const double Wgs84Flattening = 1d / 298.257223563;
         public static readonly double Wgs84Eccentricity = Math.Sqrt((2d - Wgs84Flattening) * Wgs84Flattening);
 
-        /// <summary>
-        /// Gets or sets the projection center. Only relevant for azimuthal projections.
-        /// </summary>
-        public Location Center { get; set; } = new Location();
-
         /// <summary>
         /// Gets or sets the WMS 1.3.0 CRS identifier.
         /// </summary>
-        public string CrsId { get; set; }
+        public string CrsId { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the projection center.
+        /// </summary>
+        public Location Center { get; set; } = new Location();
 
         /// <summary>
         /// Indicates if this is a normal cylindrical projection.
diff --git a/MapControl/Shared/ViewTransform.cs b/MapControl/Shared/ViewTransform.cs
index f7dc0663..36d89193 100644
--- a/MapControl/Shared/ViewTransform.cs
+++ b/MapControl/Shared/ViewTransform.cs
@@ -19,6 +19,16 @@ namespace MapControl
     /// </summary>
     public class ViewTransform
     {
+        public static double ZoomLevelToScale(double zoomLevel)
+        {
+            return 256d * Math.Pow(2d, zoomLevel) / (360d * MapProjection.Wgs84MetersPerDegree);
+        }
+
+        public static double ScaleToZoomLevel(double scale)
+        {
+            return Math.Log(scale * 360d * MapProjection.Wgs84MetersPerDegree / 256d, 2d);
+        }
+
         /// <summary>
         /// Gets the scaling factor from cartesian map coordinates to view coordinates,
         /// i.e. pixels per meter.
@@ -117,15 +127,5 @@ namespace MapControl
             return new MatrixTransform { Matrix = transform }
                 .TransformBounds(new Rect(0d, 0d, viewSize.Width, viewSize.Height));
         }
-
-        public static double ZoomLevelToScale(double zoomLevel)
-        {
-            return 256d * Math.Pow(2d, zoomLevel) / (360d * MapProjection.Wgs84MetersPerDegree);
-        }
-
-        public static double ScaleToZoomLevel(double scale)
-        {
-            return Math.Log(scale * 360d * MapProjection.Wgs84MetersPerDegree / 256d, 2d);
-        }
     }
 }