Converted the project to .NET 9

.gitignore

@@ -1,3 +1,6 @@
 packages
 bin
-obj
+obj
+.vs
+*.user
+*.bak

TurfCS/Helpers.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using GeoJSON.Net.Feature;
 using GeoJSON.Net.Geometry;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
 
 namespace TurfCS
 {

TurfCS/Joins.cs

@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using GeoJSON.Net;
 using GeoJSON.Net.Feature;
 using GeoJSON.Net.Geometry;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
 
 namespace TurfCS
 {
@@ -36,7 +38,7 @@ static public bool Inside(Feature point, Feature poly)
 			if (type == GeoJSONObjectType.Polygon)
 				return Inside_(Turf.GetCoord(point), new List<Polygon>() { (Polygon)poly.Geometry });
 			else if (type == GeoJSONObjectType.MultiPolygon)
-				return Inside_(Turf.GetCoord(point), ((MultiPolygon)poly.Geometry).Coordinates);
+				return Inside_(Turf.GetCoord(point), ((MultiPolygon)poly.Geometry).Coordinates.ToList());
 			else
 				throw new Exception("2nd argument must be Polygon or MultiPolygon");
 		}

TurfCS/Measurement.cs

@@ -4,6 +4,7 @@
 using GeoJSON.Net;
 using GeoJSON.Net.Feature;
 using GeoJSON.Net.Geometry;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
 
 namespace TurfCS
 {
@@ -564,7 +565,7 @@ public static double LineDistance(IGeoJSONObject line, string units = "kilometer
 
 			if (geometry.Type == GeoJSONObjectType.LineString)
 			{
-				return Length(((LineString)geometry).Coordinates, units);
+				return Length(((LineString)geometry).Coordinates.ToList(), units);
 			}
 			else if (geometry.Type == GeoJSONObjectType.Polygon || geometry.Type == GeoJSONObjectType.MultiLineString)
 			{
@@ -574,7 +575,7 @@ public static double LineDistance(IGeoJSONObject line, string units = "kilometer
 				for (var i = 0; i < lines.Count; i++)
 				{
 					var points = ((LineString)lines[i]).Coordinates;
-					d += Length(points, units);
+					d += Length(points.ToList(), units);
 				}
 				return d;
 			}
@@ -588,7 +589,7 @@ public static double LineDistance(IGeoJSONObject line, string units = "kilometer
 					for (var j = 0; j < lines.Count; j++)
 					{
 						var points = ((LineString)lines[j]).Coordinates;
-						d += Length(points, units);
+						d += Length(points.ToList(), units);
 					}
 				}
 				return d;

TurfCS/Meta.cs

@@ -4,6 +4,7 @@
 using GeoJSON.Net;
 using GeoJSON.Net.Feature;
 using GeoJSON.Net.Geometry;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
 
 namespace TurfCS
 {
@@ -110,7 +111,7 @@ static private void CoordEach(IGeometryObject layer, Action<GeographicPosition>
 				else if (geometry.Type == GeoJSONObjectType.LineString || geometry.Type == GeoJSONObjectType.MultiPoint)
 				{
 					var coords = geometry.Type == GeoJSONObjectType.LineString ?
-										 ((LineString)layer).Coordinates :
+										 ((LineString)layer).Coordinates.ToList() :
 										 ((MultiPoint)layer).Coordinates.Select(x => x.Coordinates).ToList();
 					for (var j = 0; j < coords.Count; j++) callback((GeographicPosition)coords[j]);
 				}
@@ -188,7 +189,7 @@ static public object CoordReduce(IGeoJSONObject layer, Func<object, GeographicPo
 		 *   // props is equal to { foo: 1}
 		 * });
 		 */
-		static public void PropEach(IGeoJSONObject layer, Action<Dictionary<string, object>, int> callback)
+		static public void PropEach(IGeoJSONObject layer, Action<IDictionary<string, object>, int> callback)
 		{
 			if (layer.Type == GeoJSONObjectType.FeatureCollection)
 			{

TurfCS/Misc.cs

@@ -1,8 +1,7 @@
-using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using GeoJSON.Net;
 using GeoJSON.Net.Feature;
-using GeoJSON.Net.Geometry;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
 
 namespace TurfCS
 {

TurfCS/Tin.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using GeoJSON.Net.Feature;
 using GeoJSON.Net.Geometry;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
 
 namespace TurfCS
 {

TurfCS/TurfCS.csproj

@@ -1,52 +1,14 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project Sdk="Microsoft.NET.Sdk">
+
   <PropertyGroup>
-    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
-    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProjectGuid>{95641025-2C48-4B98-9345-97D91AB40BBA}</ProjectGuid>
-    <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
-    <OutputType>Library</OutputType>
     <RootNamespace>TurfCS</RootNamespace>
     <AssemblyName>TurfCS</AssemblyName>
-    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
-    <TargetFrameworkProfile>Profile111</TargetFrameworkProfile>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <LangVersion>preview</LangVersion>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
-    <DebugSymbols>true</DebugSymbols>
-    <DebugType>full</DebugType>
-    <Optimize>false</Optimize>
-    <OutputPath>bin\Debug</OutputPath>
-    <DefineConstants>DEBUG;</DefineConstants>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-  </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
-    <Optimize>true</Optimize>
-    <OutputPath>bin\Release</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-  </PropertyGroup>
-  <ItemGroup>
-    <Compile Include="Helpers.cs" />
-    <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="Meta.cs" />
-    <Compile Include="Joins.cs" />
-    <Compile Include="Tin.cs" />
-    <Compile Include="Measurement.cs" />
-    <Compile Include="Assertions.cs" />
-    <Compile Include="Classification.cs" />
-    <Compile Include="Misc.cs" />
-  </ItemGroup>
-  <ItemGroup>
-    <Reference Include="GeoJSON.Net">
-      <HintPath>..\packages\GeoJSON.Net.0.1.51\lib\portable-net40+sl5+wp80+win8+wpa81\GeoJSON.Net.dll</HintPath>
-    </Reference>
-    <Reference Include="Newtonsoft.Json">
-      <HintPath>..\packages\Newtonsoft.Json.9.0.1\lib\portable-net45+wp80+win8+wpa81\Newtonsoft.Json.dll</HintPath>
-    </Reference>
-  </ItemGroup>
+
   <ItemGroup>
-    <None Include="packages.config" />
+    <PackageReference Include="GeoJSON.Net" Version="1.4.1" />
   </ItemGroup>
-  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
-</Project>
+
+</Project>

TurfCSTest/AssertionsTest.cs

@@ -1,81 +1,81 @@
-using System;
-using GeoJSON.Net.Feature;
+using GeoJSON.Net.Feature;
 using GeoJSON.Net.Geometry;
 using Newtonsoft.Json;
 using NUnit.Framework;
 using TurfCS;
+using Assert= NUnit.Framework.Legacy.ClassicAssert;
 
 namespace TurfCSTest
 {
 	[TestFixture()]
-	public class AssertionsTest
-	{
-		[Test()]
-		public void Bbox()
-		{
-			var fc = JsonConvert.DeserializeObject<FeatureCollection>(Tools.GetResource("bbox.FeatureCollection.geojson"));
-			var pt = JsonConvert.DeserializeObject<Feature>(Tools.GetResource("bbox.Point.geojson"));
-			var line = JsonConvert.DeserializeObject<LineString>(Tools.GetResource("bbox.LineString.geojson"));
-			var poly = JsonConvert.DeserializeObject<Feature>(Tools.GetResource("bbox.Polygon.geojson"));
-			var multiLine = JsonConvert.DeserializeObject<MultiLineString>(Tools.GetResource("bbox.MultiLineString.geojson"));
-			var multiPoly = JsonConvert.DeserializeObject<MultiPolygon>(Tools.GetResource("bbox.MultiPolygon.geojson"));
+    public class AssertionsTest
+    {
+        [Test()]
+        public void Bbox()
+        {
+            var fc = JsonConvert.DeserializeObject<FeatureCollection>(Tools.GetResource("bbox.FeatureCollection.geojson"));
+            var pt = JsonConvert.DeserializeObject<Feature>(Tools.GetResource("bbox.Point.geojson"));
+            var line = JsonConvert.DeserializeObject<LineString>(Tools.GetResource("bbox.LineString.geojson"));
+            var poly = JsonConvert.DeserializeObject<Feature>(Tools.GetResource("bbox.Polygon.geojson"));
+            var multiLine = JsonConvert.DeserializeObject<MultiLineString>(Tools.GetResource("bbox.MultiLineString.geojson"));
+            var multiPoly = JsonConvert.DeserializeObject<MultiPolygon>(Tools.GetResource("bbox.MultiPolygon.geojson"));
 
-			// FeatureCollection
+            // FeatureCollection
 			var fcExtent = Turf.Bbox(fc);
 			Assert.AreEqual(fcExtent[0], 20);
 			Assert.AreEqual(fcExtent[1], -10);
 			Assert.AreEqual(fcExtent[2], 130);
 			Assert.AreEqual(fcExtent[3], 4);
 
-			// Point
-			var ptExtent = Turf.Bbox(pt);
+            // Point
+            var ptExtent = Turf.Bbox(pt);
 			Assert.AreEqual(ptExtent[0], 102);
 			Assert.AreEqual(ptExtent[1], 0.5);
 			Assert.AreEqual(ptExtent[2], 102);
 			Assert.AreEqual(ptExtent[3], 0.5);
 
-			// Line
-			var lineExtent = Turf.Bbox(line);
+            // Line
+            var lineExtent = Turf.Bbox(line);
 			Assert.AreEqual(lineExtent[0], 102);
 			Assert.AreEqual(lineExtent[1], -10);
 			Assert.AreEqual(lineExtent[2], 130);
 			Assert.AreEqual(lineExtent[3], 4);
 
-			// Polygon
-			var polyExtent = Turf.Bbox(poly);
+            // Polygon
+            var polyExtent = Turf.Bbox(poly);
 			Assert.AreEqual(polyExtent[0], 100);
 			Assert.AreEqual(polyExtent[1], 0);
 			Assert.AreEqual(polyExtent[2], 101);
 			Assert.AreEqual(polyExtent[3], 1);
 
-			// MultiLineString
-			var multiLineExtent = Turf.Bbox(multiLine);
+            // MultiLineString
+            var multiLineExtent = Turf.Bbox(multiLine);
 			Assert.AreEqual(multiLineExtent[0], 100);
 			Assert.AreEqual(multiLineExtent[1], 0);
 			Assert.AreEqual(multiLineExtent[2], 103);
 			Assert.AreEqual(multiLineExtent[3], 3);
 
-			// MultiPolygon
-			var multiPolyExtent = Turf.Bbox(multiPoly);
+            // MultiPolygon
+            var multiPolyExtent = Turf.Bbox(multiPoly);
 			Assert.AreEqual(multiPolyExtent[0], 100);
 			Assert.AreEqual(multiPolyExtent[1], 0);
 			Assert.AreEqual(multiPolyExtent[2], 103);
 			Assert.AreEqual(multiPolyExtent[3], 3);
-		}
+        }
 
-		[Test()]
-		public void Circle()
-		{
-			var center = Turf.Point(new double[] { -75.343, 39.984 });
-			double radius = 5;
-			int steps = 10;
+        [Test()]
+        public void Circle()
+        {
+            var center = Turf.Point(new double[] { -75.343, 39.984 });
+            double radius = 5;
+            int steps = 10;
 
-			var polygon = Turf.Circle(center, radius, steps, "kilometers");
-			var point1 = Turf.Destination(center, radius - 1, 45, "kilometers");
-			var point2 = Turf.Destination(center, radius + 1, 135, "kilometers");
+            var polygon = Turf.Circle(center, radius, steps, "kilometers");
+            var point1 = Turf.Destination(center, radius - 1, 45, "kilometers");
+            var point2 = Turf.Destination(center, radius + 1, 135, "kilometers");
 
 			Assert.AreEqual(Turf.Inside(point1, polygon), true, "point is inside the polygon");
     		Assert.AreEqual(Turf.Inside(point2, polygon), false, "point is outside the polygon");
-		}
-	}
+        }
+    }
 }

TurfCSTest/ClassificationTest.cs

@@ -5,6 +5,9 @@
 using Newtonsoft.Json;
 using NUnit.Framework;
 using TurfCS;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
+using Assert= NUnit.Framework.Legacy.ClassicAssert;
+
 
 namespace TurfCSTest
 {

TurfCSTest/JoinsTest.cs

@@ -6,6 +6,8 @@
 using GeoJSON.Net.Feature;
 using TurfCS;
 using System.Linq;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
+using Assert= NUnit.Framework.Legacy.ClassicAssert;
 
 namespace TurfCSTest
 {

TurfCSTest/MeasurementTest.cs

@@ -6,6 +6,8 @@
 using Newtonsoft.Json;
 using NUnit.Framework;
 using TurfCS;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
+using Assert= NUnit.Framework.Legacy.ClassicAssert;
 
 namespace TurfCSTest
 {

TurfCSTest/MetaTest.cs

@@ -1,10 +1,11 @@
 using System;
 using System.Collections.Generic;
-using GeoJSON.Net;
 using GeoJSON.Net.Feature;
 using GeoJSON.Net.Geometry;
 using NUnit.Framework;
 using TurfCS;
+using GeographicPosition= GeoJSON.Net.Geometry.Position;
+using Assert= NUnit.Framework.Legacy.ClassicAssert;
 
 namespace TurfCSTest
 {
@@ -120,7 +121,7 @@ public void CoordEach()
 		[Test()]
 		public void PropEach()
 		{
-			Action<Dictionary<string, object>, int> callback = (Dictionary<string, object>obj, int i) =>
+			Action<IDictionary<string, object>, int> callback = (IDictionary<string, object>obj, int i) =>
 			{
 				Assert.AreEqual(obj, new Dictionary<string, object>() { { "a", 1 } });
 				Assert.AreEqual(i, 0);

TurfCSTest/TinTest.cs

@@ -4,6 +4,7 @@
 using Newtonsoft.Json;
 using NUnit.Framework;
 using TurfCS;
+using Assert= NUnit.Framework.Legacy.ClassicAssert;
 
 namespace TurfCSTest
 {

TurfCSTest/Tools.cs

@@ -22,7 +22,7 @@ public static string GetResource(string resourceName)
 			{
 				string path = Names.First(x => x.EndsWith("." + resourceName, StringComparison.CurrentCultureIgnoreCase));
 				var stream = Assembly.GetManifestResourceStream(path);
-				using (var reader = new StreamReader(stream, Encoding.UTF8))
+				using (var reader = new StreamReader(stream!, Encoding.UTF8))
 				{
 					return reader.ReadToEnd();
 				}