From 5b9e5529f6bb5dcfd2136759b259bdb1f3b56811 Mon Sep 17 00:00:00 2001
From: Clemens <fischer.clemens@gmail.com>
Date: Wed, 19 Jan 2022 23:40:05 +0100
Subject: [PATCH] Added GeoApiProjectionFactory

---
 MapProjections/Shared/GeoApiProjection.cs     |  9 +++
 .../Shared/GeoApiProjectionFactory.cs         | 70 +++++++++++++++++++
 .../Shared/PolarStereographicProjection.cs    |  6 +-
 MapProjections/Shared/UtmProjection.cs        | 18 ++++-
 MapProjections/UWP/MapProjections.UWP.csproj  |  3 +
 MapProjections/WPF/MapProjections.WPF.csproj  |  4 ++
 6 files changed, 106 insertions(+), 4 deletions(-)
 create mode 100644 MapProjections/Shared/GeoApiProjectionFactory.cs

diff --git a/MapProjections/Shared/GeoApiProjection.cs b/MapProjections/Shared/GeoApiProjection.cs
index 00b2ad2e..62f55048 100644
--- a/MapProjections/Shared/GeoApiProjection.cs
+++ b/MapProjections/Shared/GeoApiProjection.cs
@@ -106,6 +106,15 @@ namespace MapControl.Projections
             get { return isWebMercator; }
         }
 
+
+        public GeoApiProjection(string wkt = null)
+        {
+            if (wkt != null)
+            {
+                WKT = wkt;
+            }
+        }
+
         public override Point LocationToMap(Location location)
         {
             if (LocationToMapTransform == null)
diff --git a/MapProjections/Shared/GeoApiProjectionFactory.cs b/MapProjections/Shared/GeoApiProjectionFactory.cs
new file mode 100644
index 00000000..e2d771a5
--- /dev/null
+++ b/MapProjections/Shared/GeoApiProjectionFactory.cs
@@ -0,0 +1,70 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2022 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Net.Http;
+
+namespace MapControl.Projections
+{
+    public class GeoApiProjectionFactory : MapProjectionFactory
+    {
+        private readonly Dictionary<int, string> wkts = new Dictionary<int, string>();
+        private readonly HttpClient httpClient = new HttpClient();
+
+        public override MapProjection CreateProjection(string projectionDefinition)
+        {
+            var projection = base.CreateProjection(projectionDefinition);
+
+            if (projection == null &&
+                projectionDefinition.StartsWith("EPSG:") &&
+                int.TryParse(projectionDefinition.Substring(5), out int epsgCode))
+            {
+                if (epsgCode >= 32601 && epsgCode <= 32660)
+                {
+                    projection = new UtmProjection(epsgCode - 32600, true);
+                }
+                else if (epsgCode == 32661)
+                {
+                    projection = new UpsNorthProjection();
+                }
+                else if (epsgCode >= 32701 && epsgCode <= 32760)
+                {
+                    projection = new UtmProjection(epsgCode - 32700, false);
+                }
+                else if (epsgCode == 32761)
+                {
+                    projection = new UpsSouthProjection();
+                }
+                else
+                {
+                    projection = new GeoApiProjection(GetWkt(epsgCode));
+                }
+            }
+
+            return projection;
+        }
+
+        private string GetWkt(int epsgCode)
+        {
+            if (!wkts.TryGetValue(epsgCode, out string wkt))
+            {
+                var url = string.Format("https://epsg.io/{0}.wkt", epsgCode);
+
+                try
+                {
+                    wkt = httpClient.GetStringAsync(url).Result; // potential deadlock?
+                    wkts[epsgCode] = wkt;
+                }
+                catch (Exception ex)
+                {
+                    Debug.WriteLine($"GeoApiProjectionFactory.GetWkt({epsgCode}): {url}: {ex.Message}");
+                }
+            }
+
+            return wkt;
+        }
+    }
+}
diff --git a/MapProjections/Shared/PolarStereographicProjection.cs b/MapProjections/Shared/PolarStereographicProjection.cs
index 33f4c5d3..374c2019 100644
--- a/MapProjections/Shared/PolarStereographicProjection.cs
+++ b/MapProjections/Shared/PolarStereographicProjection.cs
@@ -114,14 +114,16 @@ namespace MapControl.Projections
 
     public class UpsNorthProjection : PolarStereographicProjection
     {
-        public UpsNorthProjection() : base("EPSG:32661", true, 0.994, 2e6, 2e6)
+        public UpsNorthProjection()
+            : base("EPSG:32661", true, 0.994, 2e6, 2e6)
         {
         }
     }
 
     public class UpsSouthProjection : PolarStereographicProjection
     {
-        public UpsSouthProjection() : base("EPSG:32761", false, 0.994, 2e6, 2e6)
+        public UpsSouthProjection()
+            : base("EPSG:32761", false, 0.994, 2e6, 2e6)
         {
         }
     }
diff --git a/MapProjections/Shared/UtmProjection.cs b/MapProjections/Shared/UtmProjection.cs
index fa5260cc..b584b95f 100644
--- a/MapProjections/Shared/UtmProjection.cs
+++ b/MapProjections/Shared/UtmProjection.cs
@@ -36,9 +36,23 @@ namespace MapControl.Projections
             }
         }
 
+        public UtmProjection()
+        {
+        }
+
+        public UtmProjection(int zoneNumber, bool north)
+        {
+            SetZone(zoneNumber, north);
+        }
+
+        public UtmProjection(Location location)
+        {
+            SetZone(location);
+        }
+
         public void SetZone(int zoneNumber, bool north)
         {
-            if (zoneNumber < 1 || zoneNumber > 61)
+            if (zoneNumber < 1 || zoneNumber > 60)
             {
                 throw new ArgumentException("Invalid UTM zone number.", nameof(zoneNumber));
             }
@@ -56,7 +70,7 @@ namespace MapControl.Projections
         {
             var zoneNumber = Math.Min((int)(Location.NormalizeLongitude(location.Longitude) + 180d) / 6 + 1, 60);
 
-            SetZone(zoneNumber, location.Latitude >= 0);
+            SetZone(zoneNumber, location.Latitude >= 0d);
         }
     }
 }
diff --git a/MapProjections/UWP/MapProjections.UWP.csproj b/MapProjections/UWP/MapProjections.UWP.csproj
index 274ca59b..7ab95557 100644
--- a/MapProjections/UWP/MapProjections.UWP.csproj
+++ b/MapProjections/UWP/MapProjections.UWP.csproj
@@ -43,6 +43,9 @@
     <Compile Include="..\Shared\GeoApiProjection.cs">
       <Link>GeoApiProjection.cs</Link>
     </Compile>
+    <Compile Include="..\Shared\GeoApiProjectionFactory.cs">
+      <Link>GeoApiProjectionFactory.cs</Link>
+    </Compile>
     <Compile Include="..\Shared\PolarStereographicProjection.cs">
       <Link>PolarStereographicProjection.cs</Link>
     </Compile>
diff --git a/MapProjections/WPF/MapProjections.WPF.csproj b/MapProjections/WPF/MapProjections.WPF.csproj
index 821e61d1..074d4de3 100644
--- a/MapProjections/WPF/MapProjections.WPF.csproj
+++ b/MapProjections/WPF/MapProjections.WPF.csproj
@@ -24,6 +24,10 @@
         <Compile Include="..\Shared\*.cs" />
     </ItemGroup>
 
+    <ItemGroup Condition="'$(TargetFramework)'=='net48' or '$(TargetFramework)'=='net462'">
+        <Reference Include="System.Net.Http" />
+    </ItemGroup>
+
     <ItemGroup>
         <PackageReference Include="ProjNET4GeoAPI" Version="1.4.1" />
     </ItemGroup>