make Feature.properties optional

src/GeoJSON.Net.Tests/Feature/FeatureTests.cs

@@ -29,6 +29,20 @@ public void Can_Deserialize_Point_Feature()
             Assert.AreEqual(GeoJSONObjectType.Point, feature.Geometry.Type);
         }
 
+        [Test]
+        public void Can_Deserialize_Feature_Without_Props()
+        {
+            var json = GetExpectedJson();
+
+            var feature = JsonConvert.DeserializeObject<Net.Feature.Feature>(json);
+
+            Assert.IsNotNull(feature);
+            Assert.IsNotNull(feature.Properties);
+            Assert.IsEmpty(feature.Properties);
+
+            Assert.AreEqual(GeoJSONObjectType.Polygon, feature.Geometry.Type);
+        }
+
         [Test]
         public void Can_Serialize_LineString_Feature()
         {

src/GeoJSON.Net.Tests/Feature/FeatureTests_Can_Deserialize_Feature_Without_Props.json

@@ -0,0 +1,14 @@
+{
+  "type": "Feature",
+  "geometry": {
+    "type": "Polygon",
+    "coordinates": [
+      [
+        [ 4.8892593383789062, 52.370725881211314 ],
+        [ 4.8952674865722656, 52.3711451105601 ],
+        [ 4.8920917510986328, 52.369310952782627 ],
+        [ 4.8892593383789062, 52.370725881211314 ]
+      ]
+    ]
+  }
+}

src/GeoJSON.Net/Feature/Feature.cs

@@ -39,7 +39,7 @@ public Feature(TGeometry geometry, TProps properties, string id = null)
         [JsonConverter(typeof(GeometryConverter))]
         public TGeometry Geometry { get; }
 
-        [JsonProperty(PropertyName = "properties", Required = Required.AllowNull)]
+        [JsonProperty(PropertyName = "properties", Required = Required.Default)]
         public TProps Properties { get; }
 
         /// <summary>