Resolves felt#195

Author: carstenpiepel

lib/geo/json/decoder.ex

@@ -13,7 +13,8 @@ defmodule Geo.JSON.Decoder do
     MultiLineStringZ,
     MultiPolygon,
     MultiPolygonZ,
-    GeometryCollection
+    GeometryCollection,
+    Unlocated
   }
 
   defmodule DecodeError do
@@ -194,7 +195,9 @@ defmodule Geo.JSON.Decoder do
     %MultiPolygonZ{coordinates: coordinates, srid: get_srid(crs), properties: properties}
   end
 
-  defp do_decode("Feature", nil, _properties, _id), do: nil
+  defp do_decode("Feature", nil, properties, _id) do
+    %Unlocated{properties: properties}
+  end
 
   defp do_decode("Feature", geometry, properties, _id) do
     do_decode(Map.get(geometry, "type"), Map.get(geometry, "coordinates"), properties, nil)

lib/geo/json/encoder.ex

@@ -15,7 +15,8 @@ defmodule Geo.JSON.Encoder do
     MultiLineStringZ,
     MultiPolygon,
     MultiPolygonZ,
-    GeometryCollection
+    GeometryCollection,
+    Unlocated
   }
 
   defmodule EncodeError do
@@ -149,7 +150,7 @@ defmodule Geo.JSON.Encoder do
 
   defp do_encode(%LineStringZM{coordinates: coordinates}) do
     # GeoJSON does not allow "m", and does not recognize "LineStringZM" as
-    # a type 
+    # a type
     coordinates = Enum.map(coordinates, fn {x, y, z, _m} -> [x, y, z] end)
     %{"type" => "LineString", "coordinates" => coordinates}
   end
@@ -224,6 +225,10 @@ defmodule Geo.JSON.Encoder do
     %{"type" => "MultiPolygon", "coordinates" => coordinates}
   end
 
+  defp do_encode(%Unlocated{} = _geom) do
+    %{"type" => "Feature", "geometry" => nil}
+  end
+
   defp do_encode(data) do
     raise EncodeError, message: "Unable to encode given value: #{inspect(data)}"
   end

lib/geo/unlocated.ex

@@ -0,0 +1,8 @@
+defmodule Geo.Unlocated do
+  @moduledoc """
+  Defines the Unlocated struct.
+  """
+
+  @type t :: %Geo.Unlocated{srid: integer | nil, properties: map}
+  defstruct srid: nil, properties: %{}
+end

test/geo/json_test.exs

@@ -363,7 +363,17 @@ defmodule Geo.JSON.Test do
     """
 
     geom = Jason.decode!(json) |> Geo.JSON.decode!()
-    assert is_nil(geom)
+    %Geo.Unlocated{} = geom
+    assert geom.properties["context"] == "80, Somme, Picardie"
+  end
+
+  test "Encode unlocted feature" do
+    geom = %Geo.Unlocated{properties: %{hi: "there"}}
+    json = Geo.JSON.encode!(geom) |> Jason.encode!()
+
+    assert(
+      json == "{\"geometry\":null,\"properties\":{\"hi\":\"there\"},\"type\":\"Feature\"}"
+    )
   end
 
   test "Decode feature in a feature collection with null geometry" do
@@ -384,7 +394,9 @@ defmodule Geo.JSON.Test do
     """
 
     geom = Jason.decode!(json) |> Geo.JSON.decode!()
-    assert geom.geometries == []
+    [geom] = geom.geometries
+    %Geo.Unlocated{} = geom
+    assert geom.properties["context"] == "80, Somme, Picardie"
   end
 
   property "encodes and decodes back to the correct Point struct" do