/// <summary>
/// Read the GeoJSON type value.
/// </summary>
/// <param name="jsonObject">
/// The JSON object.
/// </param>
/// <param name="coordinateSystem">
/// The coordinate System.
/// </param>
/// <returns>
/// A function that can read the value.
/// </returns>
/// <exception cref="ArgumentException">
/// Unexpected JSON.
/// </exception>
/// <remarks>
/// Leaves the reader positioned where the value should start.
/// </remarks>
public static GeoBase ParseJsonObjectToGeoBase(DbGeographyGeoJsonConverter converter, JObject jsonObject, out int? coordinateSystem)
{
var type = jsonObject["type"];
if (type == null)
{
throw new ArgumentException(string.Format("Expected a \"type\" property, found [{0}]", string.Join(", ", jsonObject.Properties().Select(p => p.Name))));
}
if (type.Type != JTokenType.String)
{
throw new ArgumentException(string.Format("Expected a string token for the type of the GeoJSON type, got {0}", type.Type), "jsonObject");
}
var crs = jsonObject["crs"];
coordinateSystem = crs != null ? converter.GetCoordinateSystem(crs.Value<JObject>()) : null;
Func<GeoBase> geoType;
if (!GeoBases.TryGetValue(type.Value<string>(), out geoType))
{
throw new ArgumentException(
string.Format(
"Got unsupported GeoJSON object type {0}. Expected one of [{1}]",
type.Value<string>(),
string.Join(", ", GeoBases.Keys)),
"jsonObject");
}
var geo = geoType();
geo.CoordinateSystem = coordinateSystem;
var isCollection = typeof(Collection).IsAssignableFrom(geo.GetType());
var geoObject = isCollection ? jsonObject["geometries"] : jsonObject["coordinates"];
if (geoObject == null)
{
throw new ArgumentException(
string.Format(
"Expected a field named \"{0}\", found [{1}]",
isCollection ? "geometries" : "coordinates",
string.Join(", ", jsonObject.Properties().Select(p => p.Name))),
"jsonObject");
}
geo.ParseJson(converter, geoObject.Value<JArray>());
coordinateSystem = geo.CoordinateSystem;
return geo;
}
