Building NTS geometries from ESRI JSON

gistfile1.cs

/// <summary>
/// Create valid <see cref="IGeometry"/> list from the incoming
/// JSON.
/// </summary>
/// <param name="geometryType">Only a single type of geometry is supported in each
/// query result, so the <paramref name="json"/> value is limited to one of the
/// <see cref="EsriGeometryType"/>s.</param>
/// <param name="json">JSON query result from <see cref="DownloadResource"/> which
/// is the raw JSON string.</param>
/// <returns>A list of point, polyline, polygon geometries in the same order
/// in which they are shown in the JSON input string.</returns>
public static IList<IGeometry> BuildGeometryFromJson(EsriGeometryType geometryType, string json)
{
	JObject jsonObject = JObject.Parse(json);
	IEnumerable<JToken> geometries = from g in jsonObject["features"].Children()
					 select g["geometry"];

	IList<IGeometry> list;
	switch (geometryType)
	{
		case EsriGeometryType.EsriGeometryPoint:
			IList<IGeometry> points = (from p in geometries
						  select new Point((double) p["x"], (double) p["y"], Double.NaN))
				.Cast<IGeometry>()
				.ToList();
			list = points;
			break;

		case EsriGeometryType.EsriGeometryPolygon:
			throw new NotImplementedException("Polygon deserialization from JSON has not been completed yet.");
			
		case EsriGeometryType.EsriGeometryPolyline:
			IList<IGeometry> lineStrings = new List<IGeometry>();

			IEnumerable<JEnumerable<JToken>> allPaths = from p in jsonObject["features"].Children()["geometry"]
								    select p["paths"].Children();

			foreach (var eachPolylineInPath in allPaths)
			{
				ICoordinate[] linePoints = (from line in eachPolylineInPath.Children()
							   select new Coordinate((double) line[0], (double) line[1], double.NaN))
					.Cast<ICoordinate>()
					.ToArray();
				lineStrings.Add(new LineString(linePoints));
			}

			list = lineStrings;
			break;

		default:
			throw new ApplicationException(String.Format(Resources.UnsupportedGeometryType, geometryType));
	}

	return list;
}