Respect the PrecisionModel grid when serializing coordinates. (NetTopologySuite#135)

Author: MizardX

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/GeoJsonConverterFactory.cs

@@ -202,7 +202,7 @@ public override JsonConverter CreateConverter(Type typeToConvert, JsonSerializer
             if (GeometryTypes.Contains(typeToConvert))
                 return new StjGeometryConverter(_factory, _writeGeometryBBox, _ringOrientationOption);
             if (typeToConvert == typeof(Envelope))
-                return new StjEnvelopeConverter();
+                return new StjEnvelopeConverter(_factory.PrecisionModel);
             if (typeToConvert == typeof(FeatureCollection))
                 return new StjFeatureCollectionConverter(_writeGeometryBBox);
             if (typeof(IFeature).IsAssignableFrom(typeToConvert))

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/StjEnvelopeConverter.cs

@@ -1,14 +1,19 @@
 using NetTopologySuite.Geometries;
 using System;
-using System.Collections.Generic;
-using System.Text;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
 namespace NetTopologySuite.IO.Converters
 {
     internal class StjEnvelopeConverter : JsonConverter<Envelope>
     {
+        private readonly PrecisionModel _precisionModel;
+
+        public StjEnvelopeConverter(PrecisionModel precisionModel)
+        {
+            _precisionModel = precisionModel;
+        }
+
         public override Envelope Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
             Envelope res = null;
@@ -22,19 +27,19 @@ public override Envelope Read(ref Utf8JsonReader reader, Type typeToConvert, Jso
             {
                 reader.ReadToken(JsonTokenType.StartArray);
 
-                double minX = reader.GetDouble();
+                double minX = reader.GetDouble(_precisionModel);
                 reader.Read();
-                double minY = reader.GetDouble();
+                double minY = reader.GetDouble(_precisionModel);
                 reader.Read();
-                double maxX = reader.GetDouble();
+                double maxX = reader.GetDouble(_precisionModel);
                 reader.Read();
-                double maxY = reader.GetDouble();
+                double maxY = reader.GetDouble(_precisionModel);
                 reader.Read();
 
                 if (reader.TokenType == JsonTokenType.Number)
                 {
                     maxX = maxY;
-                    maxY = reader.GetDouble();
+                    maxY = reader.GetDouble(_precisionModel);
                     reader.Read();
                     reader.Read();
                 }
@@ -59,10 +64,10 @@ public override void Write(Utf8JsonWriter writer, Envelope value, JsonSerializer
             }
 
             writer.WriteStartArray();
-            writer.WriteNumberValue(value.MinX);
-            writer.WriteNumberValue(value.MinY);
-            writer.WriteNumberValue(value.MaxX);
-            writer.WriteNumberValue(value.MaxY);
+            writer.WriteNumberValue(value.MinX, _precisionModel);
+            writer.WriteNumberValue(value.MinY, _precisionModel);
+            writer.WriteNumberValue(value.MaxX, _precisionModel);
+            writer.WriteNumberValue(value.MaxY, _precisionModel);
             writer.WriteEndArray();
         }
     }

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/StjGeometryConverter.Coordinates.cs

@@ -8,7 +8,6 @@ internal partial class StjGeometryConverter
     {
         private void WriteCoordinateSequence(Utf8JsonWriter writer, CoordinateSequence sequence, JsonSerializerOptions options, bool multiple = true, OrientationIndex orientation = OrientationIndex.None)
         {
-            //writer.WritePropertyName("coordinates");
             if (sequence == null)
             {
                 writer.WriteNullValue();
@@ -29,15 +28,17 @@ private void WriteCoordinateSequence(Utf8JsonWriter writer, CoordinateSequence s
             for (int i = 0; i < sequence.Count; i++)
             {
                 writer.WriteStartArray();
-                writer.WriteNumberValue(sequence.GetX(i));
-                writer.WriteNumberValue(sequence.GetY(i));
+
+                writer.WriteNumberValue(sequence.GetX(i), _geometryFactory.PrecisionModel);
+                writer.WriteNumberValue(sequence.GetY(i), _geometryFactory.PrecisionModel);
 
                 if (hasZ)
                 {
                     double z = sequence.GetZ(i);
                     if (!double.IsNaN(z))
-                        writer.WriteNumberValue(sequence.GetZ(i));
+                        writer.WriteNumberValue(z, _geometryFactory.PrecisionModel);
                 }
+
                 writer.WriteEndArray();
 
                 if (!multiple) break;

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/Utility.cs

@@ -7,6 +7,7 @@
 using System.Text.Json.Nodes;
 using System.Text.Json.Serialization;
 using NetTopologySuite.Features;
+using NetTopologySuite.Geometries;
 using NetTopologySuite.IO.Properties;
 
 namespace NetTopologySuite.IO.Converters
@@ -103,5 +104,23 @@ private static string CurrentTokenAsString(in Utf8JsonReader reader)
                 ? reader.ValueSequence.ToArray()
                 : reader.ValueSpan.ToArray());
         }
+
+        /// <summary>
+        /// Parses the current JSON token value from the source as a <see cref="double"/>. Rounds a value to the <see cref="PrecisionModel"/> grid.
+        /// </summary>
+        /// <param name="reader">The reader.</param>
+        /// <param name="precisionModel">The precision model to round to.</param>
+        /// <returns>The rounded value</returns>
+        internal static double GetDouble(this Utf8JsonReader reader, PrecisionModel precisionModel)
+            => precisionModel.MakePrecise(reader.GetDouble());
+
+        /// <summary>
+        /// Rounds a <see cref="double"/> value to the <see cref="PrecisionModel"/> grid. Writes the rounded value (as a JSON number) as an element of a JSON array.
+        /// </summary>
+        /// <param name="writer">The writer.</param>
+        /// <param name="value">The value to write.</param>
+        /// <param name="precisionModel">The precision model to round to.</param>
+        internal static void WriteNumberValue(this Utf8JsonWriter writer, double value, PrecisionModel precisionModel)
+            => writer.WriteNumberValue(precisionModel.MakePrecise(value));
     }
 }

test/NetTopologySuite.IO.GeoJSON4STJ.Test/Issues/Issue135.cs

@@ -0,0 +1,37 @@
+using NetTopologySuite.Geometries;
+using NetTopologySuite.IO.Converters;
+using NetTopologySuite.IO.GeoJSON4STJ.Test.Converters;
+using NUnit.Framework;
+using System.Text.Json;
+
+namespace NetTopologySuite.IO.GeoJSON4STJ.Test.Issues
+{
+    internal class Issue135 : SandDTest<Geometry>
+    {
+        [Test, GeoJsonIssueNumber(135)]
+        public void TestOutputPrecision()
+        {
+            var coords = new[]
+            {
+                new Coordinate(0.001, 0.001),
+                new Coordinate(10.1, 0.002),
+                new Coordinate(10, 10.1),
+                new Coordinate(0.05, 9.999),
+                new Coordinate(0.001, 0.001)
+            };
+            var factory = new GeometryFactory(new PrecisionModel(10), 4326);
+            var polygon = factory.CreatePolygon(coords);
+
+            string json = JsonSerializer.Serialize(polygon, new JsonSerializerOptions
+            {
+                ReadCommentHandling = JsonCommentHandling.Skip,
+                Converters =
+                {
+                    new GeoJsonConverterFactory(factory)
+                }
+            });
+
+            Assert.That(json, Is.EqualTo("{\"type\":\"Polygon\",\"coordinates\":[[[0,0],[10.1,0],[10,10.1],[0.1,10],[0,0]]]}"));
+        }
+    }
+}