New TransverseMercatorProjection implementation

MapControl/Shared/Wgs84UtmProjection.cs

@@ -0,0 +1,94 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// Copyright © 2024 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+
+namespace MapControl
+{
+    /// <summary>
+    /// WGS84 UTM Projection with zone number and north/south flag.
+    /// </summary>
+    public class Wgs84UtmProjection : TransverseMercatorProjection
+    {
+        public const int FirstZone = 1;
+        public const int LastZone = 60;
+        public const int FirstZoneNorthEpsgCode = 32600 + FirstZone;
+        public const int LastZoneNorthEpsgCode = 32600 + LastZone;
+        public const int FirstZoneSouthEpsgCode = 32700 + FirstZone;
+        public const int LastZoneSouthEpsgCode = 32700 + LastZone;
+
+        public int Zone { get; private set; }
+        public bool IsNorth { get; private set; }
+
+        public Wgs84UtmProjection(int zone, bool north)
+        {
+            SetZone(zone, north);
+        }
+
+        protected void SetZone(int zone, bool north)
+        {
+            if (zone < FirstZone || zone > LastZone)
+            {
+                throw new ArgumentException($"Invalid WGS84 UTM zone {zone}.", nameof(zone));
+            }
+
+            Zone = zone;
+            IsNorth = north;
+            CrsId = $"EPSG:{(north ? 32600 : 32700) + zone}";
+            EquatorialRadius = Wgs84EquatorialRadius;
+            Flattening = Wgs84Flattening;
+            ScaleFactor = 0.9996;
+            CentralMeridian = Zone * 6d - 183d;
+            FalseEasting = 5e5;
+            FalseNorthing = IsNorth ? 0d : 1e7;
+        }
+    }
+
+    /// <summary>
+    /// WGS84 UTM Projection with automatic zone selection from projection center.
+    /// </summary>
+    public class Wgs84AutoUtmProjection : Wgs84UtmProjection
+    {
+        public const string DefaultCrsId = "AUTO2:42001";
+
+        private readonly string autoCrsId;
+
+        public Wgs84AutoUtmProjection(string crsId = DefaultCrsId)
+            : base(31, true)
+        {
+            autoCrsId = crsId;
+
+            if (!string.IsNullOrEmpty(autoCrsId))
+            {
+                CrsId = autoCrsId;
+            }
+        }
+
+        public override Location Center
+        {
+            get => base.Center;
+            protected internal set
+            {
+                if (!Equals(base.Center, value))
+                {
+                    base.Center = value;
+
+                    var lon = Location.NormalizeLongitude(value.Longitude);
+                    var zone = (int)Math.Floor(lon / 6d) + 31;
+                    var north = value.Latitude >= 0d;
+
+                    if (Zone != zone || IsNorth != north)
+                    {
+                        SetZone(zone, north);
+
+                        if (!string.IsNullOrEmpty(autoCrsId))
+                        {
+                            CrsId = autoCrsId;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}