Fix misplacement of geometry parts

.github/workflows/dotnetcore.yml

@@ -19,10 +19,10 @@ jobs:
 
     steps:
     - name: Get source
-      uses: actions/checkout@v1
+      uses: actions/checkout@v4
 
     - name: Setup .NET Core 6.
-      uses: actions/setup-dotnet@v1
+      uses: actions/setup-dotnet@v4
       with:
         dotnet-version: 6.0.x
 

.github/workflows/prerelease.yml

@@ -11,11 +11,11 @@ jobs:
 
     steps:
     - name: Get source
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
       with:
         submodules: 'true'
     - name: Setup .NET Core 6.
-      uses: actions/setup-dotnet@v1
+      uses: actions/setup-dotnet@v4
       with:
         dotnet-version: 6.0.x
     - name: Restore packages.

.github/workflows/release.yml

@@ -11,11 +11,11 @@ jobs:
 
     steps:
     - name: Get source
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
       with:
         submodules: 'true'
     - name: Setup .NET Core 6.
-      uses: actions/setup-dotnet@v1
+      uses: actions/setup-dotnet@v4
       with:
         dotnet-version: 6.0.x
     - name: Restore packages.

README.md

@@ -8,7 +8,7 @@ A package that can be used to read or generate vector tiles using NTS.
 
 ## Getting started
 
-This package is somewhat experimental. A NuGet-package is hosted on [Github Packages](https://github.com/orgs/NetTopologySuite/packages?repo_name=NetTopologySuite.IO.VectorTiles) 
+A NuGet-package is hosted on [Github Packages](https://github.com/orgs/NetTopologySuite/packages?repo_name=NetTopologySuite.IO.VectorTiles) 
 
 ### Create a vector tile
 
@@ -34,10 +34,19 @@ vt.Layers.Add(lyr);
 using (var fs = new FileStream(filePath, FileMode.Create))
 {
     //Write the tile to the stream.
-    vt.Write(fs);
+    vt.Write(fs, MapboxTileWriter.DefaultMinLinealExtent, MapboxTileWriter.DefaultMinPolygonalExtent);
 }
 ```
 
+`MapboxTileWriter.Write` method takes two arguments controlling the output of features.
+
+Argument | Default | Meaning
+--- | --- | ---
+minLinealExtent | 1 pixel |This applies to features with lineal geometries. If their scaled geometries for this tile have a bounding box with both edge lengths less than this value will not be written
+minPolygonalExtent | 2 pixel<sup>2</sup> | This applies to polygonal geometries. If their scaled geometries for this tile have a bounding box with an area less than this value will not be exported.
+
+Both constraints apply to parts of geometries, too. Holes in polygons or parts of multi-geometries not meeting the requirement will be omitted.
+
 ### Read a vector tile
 
 The following shows how to read an individual vector tile and access the underlying NTS Features.
@@ -127,10 +136,10 @@ vt.Layers.Add(lyr);
 using (var fs = new FileStream(filePath, FileMode.Create))
 {
     //Write the tile to the stream. This will automatically look for an "id" attribute that is a ulong or integer value as set the tile's feature ID to it.
-    vt.Write(fs);
+    vt.Write(fs, MapboxTileWriter.DefaultMinLinealExtent, MapboxTileWriter.DefaultMinPolygonalExtent);
 
     //Alternatively, pass in a different attribute name to have the vector tiles feature use that ID value.
-    //vt.Write(fs, 4096, "alternateId");
+    //vt.Write(fs, MapboxTileWriter.DefaultMinLinealExtent, MapboxTileWriter.DefaultMinPolygonalExtent, 4096, "alternateId");
 }
 ```
 

src/NetTopologySuite.IO.VectorTiles.Mapbox/TileGeometryTransform.cs

@@ -105,18 +105,27 @@ public bool IsPointInExtent(int x, int y)
         /// </summary>
         /// <param name="polygon">Polygon to test.</param>
         /// <returns>true if the <paramref name="polygon"/> is greater than 1 pixel in the tile pixel coordinates</returns>
-        public bool IsGreaterThanOnePixelOfTile(Geometry polygon)
+        public bool IsGreaterThanOnePixelOfTile(Geometry geometry)
         {
-            if (polygon.IsEmpty) return false;
+            if (geometry.IsEmpty) return false;
 
-            (double x1, double y1) = WebMercatorHandler.FromMetersToPixels(WebMercatorHandler.LatLonToMeters(polygon.EnvelopeInternal.MinY, polygon.EnvelopeInternal.MinX), ZoomResolution);
-            (double x2, double y2) = WebMercatorHandler.FromMetersToPixels(WebMercatorHandler.LatLonToMeters(polygon.EnvelopeInternal.MaxY, polygon.EnvelopeInternal.MaxX), ZoomResolution);
+            var env = geometry.EnvelopeInternal;
+            (double x1, double y1) = WebMercatorHandler.FromMetersToPixels(WebMercatorHandler.LatLonToMeters(env.MinY, env.MinX), ZoomResolution);
+            (double x2, double y2) = WebMercatorHandler.FromMetersToPixels(WebMercatorHandler.LatLonToMeters(env.MaxY, env.MaxX), ZoomResolution);
 
             double dx = Math.Abs(x2 - x1);
             double dy = Math.Abs(y2 - y1);
 
             // Both must be greater than 0, and at least one of them needs to be larger than 1. 
             return dx > 0 && dy > 0 && (dx > 1 || dy > 1);
         }
+
+        public (long x, long y) ExtentInPixel(Envelope env)
+        {
+            (long minX, long minY) = WebMercatorHandler.FromMetersToPixels(WebMercatorHandler.LatLonToMeters(env.MinY, env.MinX), ZoomResolution);
+            (long maxX, long maxY) = WebMercatorHandler.FromMetersToPixels(WebMercatorHandler.LatLonToMeters(env.MaxY, env.MaxX), ZoomResolution);
+
+            return (maxX - minX, maxY - minY);
+        }
     }
 }

test/NetTopologySuite.IO.VectorTiles.Samples/NetTopologySuite.IO.VectorTiles.Samples.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>net5.0</TargetFramework>
+    <TargetFramework>net6.0</TargetFramework>
     <CopyRefAssembliesToPublishDirectory>false</CopyRefAssembliesToPublishDirectory>
   </PropertyGroup>
 
@@ -34,7 +34,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation" Version="5.0.7" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation" Version="6.0.28" />
     <PackageReference Include="NetTopologySuite.IO.GeoJSON" Version="2.0.2" />
   </ItemGroup>
 

test/NetTopologySuite.IO.VectorTiles.Samples/Startup.cs

@@ -113,7 +113,7 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 
             tree.GetExtents(out Pages.IndexModel._BBox, out Pages.IndexModel._MinZoom, out Pages.IndexModel._MaxZoom);
 
-            tree.Write("wwwroot/tiles");
+            tree.Write("wwwroot/tiles", MapboxTileWriter.DefaultMinLinealExtent, MapboxTileWriter.DefaultMinPolygonalExtent);
         }
     }
 }

test/NetTopologySuite.IO.VectorTiles.Tests.Functional/Program.cs

@@ -56,7 +56,7 @@ private static void RunTest(string fileName, int minZoom, int maxZoom, string st
             };
 
             // write the tiles to disk as mvt.
-            Mapbox.MapboxTileWriter.Write(tree, "tiles");
+            Mapbox.MapboxTileWriter.Write(tree, "tiles", 1, 2);
 
             stopwatch.Stop();
 

test/NetTopologySuite.IO.VectorTiles.Tests/Issues/Issue29.cs

@@ -0,0 +1,52 @@
+using NetTopologySuite.Features;
+using NetTopologySuite.Geometries;
+using NetTopologySuite.IO.VectorTiles.Mapbox;
+using System.Collections.Generic;
+using System.IO;
+using Xunit;
+
+namespace NetTopologySuite.IO.VectorTiles.Tests.Issues
+{
+    public class Issue29
+    {
+        [Fact]
+        public void MvtWriterGeometryIssue()
+        {
+            WriteTile(8, 6, 4);
+            WriteTile(8, 5, 4);
+            WriteTile(34, 24, 6);
+        }
+
+        private static void WriteTile(int x, int y, int z)
+        {
+            var geometry = new WKTReader().Read(ItalyWkt);
+            var feature = new Feature(geometry, new AttributesTable(new Dictionary<string, object>()
+        {
+            { "id", 1 }
+        }));
+            var tileDefinition = new VectorTiles.Tiles.Tile(x, y, z);
+            var vectorTile = new VectorTile { TileId = tileDefinition.Id };
+            var layer = new Layer { Name = "layer1" };
+            vectorTile.Layers.Add(layer);
+            layer.Features.Add(feature);
+
+            byte[] result;
+            MemoryStream? ms;
+            using (ms = new MemoryStream(1024 * 32))
+            {
+                vectorTile.Write(ms, MapboxTileWriter.DefaultMinLinealExtent, MapboxTileWriter.DefaultMinPolygonalExtent);
+                result = ms.ToArray();
+            }
+
+            File.WriteAllBytes($"{x}_{y}_{z}.mvt", result);
+        }
+
+        private static string ItalyWkt
+        {
+            get
+            {
+                return File.ReadAllText(Path.Combine("Issues", $"{typeof(Issue29).Name}.wkt"));
+            }
+        }
+    }
+}

test/NetTopologySuite.IO.VectorTiles.Tests/Mapbox/FeatureIdTest.cs

@@ -42,11 +42,11 @@ private void FeatureIdReadWriteTest(Features.Feature featureS, ulong expectedId,
                 if (string.IsNullOrEmpty(idAttributeName))
                 {
                     //No ID property specified when writing.
-                    vtS.Write(ms);
+                    vtS.Write(ms, MapboxTileWriter.DefaultMinLinealExtent, MapboxTileWriter.DefaultMinPolygonalExtent);
                 }
                 else
                 {
-                    vtS.Write(ms, 4096, idAttributeName);
+                    vtS.Write(ms, MapboxTileWriter.DefaultMinLinealExtent, MapboxTileWriter.DefaultMinPolygonalExtent, 4096, idAttributeName);
                 }
                 ms.Position = 0;
 

test/NetTopologySuite.IO.VectorTiles.Tests/Mapbox/Tile.ValueTest.cs

@@ -22,7 +22,7 @@ public void TestHashCodeDontChangeOnInstance()
             Assert.Equal(hashCode, v.GetHashCode());
         }
 
-        [Fact(Skip = "This is known to fail.")]
+        [Fact/*(Skip = "This is known to fail.")*/]
         public void TestEquals()
         {
             var v1 = new Tile.Value {StringValue = "Hello"};

test/NetTopologySuite.IO.VectorTiles.Tests/NetTopologySuite.IO.VectorTiles.Tests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
@@ -8,10 +8,13 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <PackageReference Include="NetTopologySuite.IO.GeoJSON" Version="2.0.2" />
-    <PackageReference Include="xunit" Version="2.4.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+    <PackageReference Include="xunit" Version="2.7.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.7">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
   </ItemGroup>
 
   <ItemGroup>
@@ -28,4 +31,10 @@
     </None>
   </ItemGroup>
 
+  <ItemGroup>
+    <None Update="Issues\Issue29.wkt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
 </Project>

test/NetTopologySuite.IO.VectorTiles.Tests/RoundTripBase.cs

@@ -47,7 +47,9 @@
 
         protected void AssertRoundTrip(Geometry inputGeometry, Geometry expectedGeometry,
             string? name = null, IAttributesTable? properties = null, uint? id = null,
-            int expectedNumFeatures = 1, IAttributesTable? expectedProperties = null)
+            int expectedNumFeatures = 1, IAttributesTable? expectedProperties = null,
+            uint minLinealExtent = MapboxTileWriter.DefaultMinLinealExtent,
+            uint minPolygonalExtent = MapboxTileWriter.DefaultMinPolygonalExtent, bool poorQuality = false)
         {
             if (inputGeometry == null)
                 inputGeometry = FeatureGeometry;
@@ -73,32 +75,35 @@
             VectorTile? vtD = null;
             using (var ms = new MemoryStream())
             {
-                vtS.Write(ms, Extent);
+                vtS.Write(ms, minLinealExtent, minPolygonalExtent, Extent);
                 ms.Position = 0;
                 vtD = new MapboxTileReader(Factory).Read(ms, new VectorTiles.Tiles.Tile(0));
             }
 
             Assert.NotNull(vtD);
-            Assert.False(vtD.IsEmpty);
-            Assert.Equal(1, vtD.Layers.Count);
+            Assert.False(vtD.IsEmpty, "Parsed vector tile is empty");
+            Assert.Single(vtD.Layers);
             Assert.Equal(expectedNumFeatures, vtD.Layers[0].Features.Count);
             var featureD = vtD.Layers[0].Features[0];
 
             // Perform geometry checks
-            CheckGeometry(expectedGeometry, featureD.Geometry);
+            CheckGeometry(expectedGeometry, featureD.Geometry, poorQuality);
 
             // Perform attribute checks
             CheckAttributes(expectedProperties, featureD.Attributes);
         }
 
-        private void CheckGeometry(Geometry expected, Geometry parsed)
+        private void CheckGeometry(Geometry expected, Geometry parsed, bool poorQuality = false)
         {
-            // Points checked
+            // Type checked
             Assert.Equal(expected.OgcGeometryType, parsed.OgcGeometryType);
 
             // Coordinates count checked
             Assert.Equal(expected.Coordinates.Length, parsed.Coordinates.Length);
 
+            // If the conversion is known to have poor quality than don't test it.
+            if (poorQuality) return;
+
             double pixelDiff = (85.5 * 2);
             double error = 2 * System.Math.Sqrt(pixelDiff * pixelDiff * 2) / Extent;
             if (expected is IPuntal)
@@ -113,7 +118,10 @@
                 }
             }
             else
-                Assert.True(new HausdorffSimilarityMeasure().Measure(expected, parsed) > 1 - error);
+            {
+                double similarityMeasure = new HausdorffSimilarityMeasure().Measure(expected, parsed);
+                Assert.True(similarityMeasure > 1 - error, $"Similarity measure insufficient: {similarityMeasure}\n\tExpected: {expected}\n\tActual: {parsed}");
+            }
         }
 
         private void CheckAttributes(IAttributesTable expected, IAttributesTable parsed)
@@ -133,7 +141,9 @@
         }
 
         protected void AssertRoundTripEmptyTile(string inputDefinition, string? name = null,
-            IAttributesTable? properties = null, uint? id = null)
+            IAttributesTable? properties = null, uint? id = null,
+            uint minLinealExtent = MapboxTileWriter.DefaultMinLinealExtent,
+            uint minPolygonalExtent = MapboxTileWriter.DefaultMinPolygonalExtent)
         {
             var inputGeometry = ParseGeometry(inputDefinition);
 
@@ -153,7 +163,7 @@
             VectorTile? vtD = null;
             using (var ms = new MemoryStream())
             {
-                vtS.Write(ms);
+                vtS.Write(ms, minLinealExtent, minPolygonalExtent);
                 ms.Position = 0;
                 vtD = new MapboxTileReader(Factory).Read(ms, new VectorTiles.Tiles.Tile(0));
             }
@@ -164,7 +174,9 @@
 
         protected void AssertRoundTrip(string inputDefinition, string? expectedDefinition = null,
             string? name = null, IAttributesTable? properties = null, uint? id = null,
-            int expectedNumFeatures = 1, IAttributesTable? expectedProperties = null)
+            int expectedNumFeatures = 1, IAttributesTable? expectedProperties = null,
+            uint minLinealExtent = MapboxTileWriter.DefaultMinLinealExtent,
+            uint minPolygonalExtent = MapboxTileWriter.DefaultMinPolygonalExtent, bool poorQuality = false)
         {
             var input = ParseGeometry(inputDefinition);
 
@@ -173,14 +185,14 @@
                 : input.Copy();
 
             AssertRoundTrip(input, expected, name, properties, id,
-                expectedNumFeatures, expectedProperties);
+                expectedNumFeatures, expectedProperties, minLinealExtent, minPolygonalExtent, poorQuality);
         }
 
         private Geometry ParseGeometry(string definition)
         {
             if (!definition.TrimStart().StartsWith("{"))
                 return Reader.Read(definition);
             return Serializer.Deserialize<Geometry>(new JsonTextReader(new StringReader(definition)));
         }
 
         protected static IAttributesTable? ToAttributesTable(params (string Label, object? Value)[]? attributes)