DbGeography多邊形到JSON

Question

我將DbGeography多邊形存儲在數據庫中。我的控制器從數據庫獲取多邊形，我需要將它們轉換爲JSON。

var polygons = db.Areas 
    .Where(x => x.Type == type) 
    .Select(x => new ViewArea 
    { 
     Id = x.Id, 
     Type = x.Type, 
     Rate = x.Rate, 
     Polygon = x.Polygon, 
    }); 
    return Json(polygons, JsonRequestBehavior.AllowGet); 

我嘗試使用getJSON從服務器獲取多邊形，但無法將DbGeography轉換爲JSON。 如何製作，轉換？

Answer 1

首先，你可能不希望任何舊的JSON，因爲有一個標準，GeoJSON。

您可以使用NewtonSoft JsonConverter屬性就像你DbGeography如下：

public class Foo 
    { 
     [JsonConverter(typeof(DbGeographyGeoJsonConverter))] 
     public DbGeography Polygon { get; set; } 
    } 

可以美孚的一個實例轉換爲JSON，如：

var foo = new Foo { Polygon = DbGeography.FromText(
          "Polygon((22.3 77.4, 22.5 77.5, 22.7 77.5, 22.3 77.4))") }; 
var jsonText = JsonConvert.SerializeObject(foo); 

這應該給你的東西，如：

{ 「多邊形」：{ 「類型」： 「多邊形」， 「座標」：[[[22.3,77.4]，[22.5,77.5]，[22.7,77.5]，[22.3,77.4]] ] }}

現在，DbGeographyGeoJsonConverter類是有點複雜，我下面提供的一個是不是真的完成（這裏是a more complete version）。消耗它生成的任何JSON足夠了。部分複雜問題來自於它被部分複製粘貼到我用於處理地理空間衆所周知的二進制和知名文本的其他類。

using System; 
using System.Collections.Generic; 
using System.Data.Entity.Spatial; 
using System.IO; 
using System.Linq; 
using System.Text.RegularExpressions; 

using AplPed.Common; 

using Newtonsoft.Json; 
using Newtonsoft.Json.Linq; 

/// <summary> 
/// The <see cref="DbGeography"/> GeoJSON converter 
/// </summary> 
public class DbGeographyGeoJsonConverter : JsonConverter 
{ 
    /// <summary> 
    /// Well-known-binary point value. 
    /// </summary> 
    private const int PointWkb = 1; 

    /// <summary> 
    /// Well-known-binary line value. 
    /// </summary> 
    private const int LineStringWkb = 2; 

    /// <summary> 
    /// Well-known-binary polygon value. 
    /// </summary> 
    private const int PolygonWkb = 3; 

    /// <summary> 
    /// Well-known-binary multi-point value. 
    /// </summary> 
    private const int MultiPointWkb = 4; 

    /// <summary> 
    /// Well-known-binary multi-line value. 
    /// </summary> 
    private const int MultiLineStringWkb = 5; 

    /// <summary> 
    /// Well-known-binary multi-polygon value. 
    /// </summary> 
    private const int MultiPolygonWkb = 6; 

    /// <summary> 
    /// Well-known-binary geometry collection value. 
    /// </summary> 
    private const int GeometryCollectionWkb = 7; 

    /// <summary> 
    /// Well-known-binary line value. 
    /// </summary> 
    private static readonly Dictionary<int, string> WkbTypes = 
    new Dictionary<int, string> 
    { 
     { PointWkb, "Point" }, 
     { LineStringWkb, "LineString" }, 
     { PolygonWkb, "Polygon" }, 
     { MultiPointWkb, "MultiPoint" }, 
     { MultiLineStringWkb, "MultiLineString" }, 
     { MultiPolygonWkb, "MultiPolygon" }, 
     { GeometryCollectionWkb, "GeometryCollection" } 
    }; 

    /// <summary> 
    /// The types derived from <see cref="GeoBase"/> accessed by name. 
    /// </summary> 
    private static readonly Dictionary<string, Type> GeoBases = 
    new Dictionary<string, Type> 
    { 
     { "Point", typeof(Point) }, 
     { "LineString", typeof(LineString) }, 
     { "Polygon", typeof(Polygon) }, 
     { "MultiPoint", typeof(MultiPoint) }, 
     { "MultiLineString", typeof(MultiLineString) }, 
     { "MultiPolygon", typeof(MultiPolygon) }, 
     { "GeometryCollection", typeof(Collection) }, 
    }; 

    /// <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(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"); 
     } 

     Type 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 geoObject = geoType == typeof(Collection) ? jsonObject["geometries"] : jsonObject["coordinates"]; 
     if (geoObject == null) 
     { 
      throw new ArgumentException(
      string.Format(
      "Expected a field named \"{0}\", found [{1}]", 
      geoType == typeof(Collection) ? "geometries" : "coordinates", 
      string.Join(", ", jsonObject.Properties().Select(p => p.Name))), 
      "jsonObject"); 
     } 

     var crs = jsonObject["crs"]; 
     coordinateSystem = crs != null ? ParseCrs(crs.Value<JObject>()) : null; 

     var geo = (GeoBase)Activator.CreateInstance(geoType); 
     geo.ParseJson(geoObject.Value<JArray>()); 
     return geo; 
    } 

    /// <inheritdoc/> 
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) 
    { 
     BinaryReader lebr; 
     BinaryReader bebr; 
     var geographyValue = value as DbGeography; 
     int coordinateSystemId; 
     if (geographyValue != null) 
     { 
      var br = new BinaryReader(new MemoryStream(geographyValue.AsBinary())); 
      lebr = BitConverter.IsLittleEndian ? br : new ReverseEndianBinaryReader(br.BaseStream); 
      bebr = BitConverter.IsLittleEndian ? new ReverseEndianBinaryReader(br.BaseStream) : br; 
      coordinateSystemId = geographyValue.CoordinateSystemId; 
     } 
     else 
     { 
      var geometryValue = value as DbGeometry; 
      if (geometryValue != null) 
      { 
       var br = new BinaryReader(new MemoryStream(geometryValue.AsBinary())); 
       lebr = BitConverter.IsLittleEndian ? br : new ReverseEndianBinaryReader(br.BaseStream); 
       bebr = BitConverter.IsLittleEndian ? new ReverseEndianBinaryReader(br.BaseStream) : br; 
       coordinateSystemId = geometryValue.CoordinateSystemId; 
      } 
      else 
      { 
       throw new ArgumentException(
       string.Format("Expecting DbGeography or DbGeometry, got {0}", value.GetType().CSharpName()), "value"); 
      } 
     } 

     var jsonObject = WriteObject(lebr, bebr); 
     jsonObject.Add(
     "crs", 
     new JObject 
     { 
      new JProperty("type", "name"), 
      new JProperty(
      "properties", 
      new JObject { new JProperty("name", string.Format("EPSG:{0}", coordinateSystemId)) }) 
     }); 
     writer.WriteRawValue(jsonObject.ToString(Formatting.None)); 
    } 

    /// <inheritdoc/> 
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) 
    { 
     // Load JObject from stream 
     JObject jsonObject = JObject.Load(reader); 

     // Create target object based on JObject 
     object target = CreateDbGeo(jsonObject, objectType); 

     // Populate the object properties 
     serializer.Populate(jsonObject.CreateReader(), target); 

     return target; 
    } 

    /// <inheritdoc/> 
    public override bool CanConvert(Type objectType) 
    { 
     return objectType == typeof(DbGeography) || objectType == typeof(DbGeometry); 
    } 

    /// <summary> 
    /// Parse the coordinate system object and return it's value. 
    /// </summary> 
    /// <param name="jsonObject"> 
    /// The JSON object. 
    /// </param> 
    /// <returns> 
    /// The coordinate system value; null if couldn't parse it (only a couple EPSG-style values). 
    /// </returns> 
    private static int? ParseCrs(JObject jsonObject) 
    { 
     var properties = jsonObject["properties"]; 
     if (properties != null && properties.Type == JTokenType.Object) 
     { 
      var p = properties.Value<JObject>(); 
      var name = p["name"]; 
      if (name != null) 
      { 
       var s = name.Value<string>(); 
       if (!string.IsNullOrWhiteSpace(s)) 
       { 
        var m = Regex.Match(
        s, 
        @"^\s*(urn\s*:\s*ogc\s*:\s*def\s*:crs\s*:EPSG\s*:\s*[\d.]*\s*:|EPSG\s*:)\s*(?<value>\d+)\s*$", 
        RegexOptions.ExplicitCapture | RegexOptions.IgnoreCase); 
        if (m.Success) 
        { 
         return int.Parse(m.Groups["value"].Value); 
        } 
       } 
      } 
     } 

     return null; 
    } 

    /// <summary> 
    /// Get well known binary from a <see cref="JsonReader"/>. 
    /// </summary> 
    /// <param name="jsonObject"> 
    /// The JSON object. 
    /// </param> 
    /// <param name="defaultCoordinateSystemId"> 
    /// The default coordinate system id. 
    /// </param> 
    /// <returns> 
    /// A tuple of the well-known-binary and the coordinate system identifier. 
    /// </returns> 
    /// <exception cref="ArgumentException"> 
    /// Unexpected JSON. 
    /// </exception> 
    private static Tuple<byte[], int> GetWellKnownBinary(JObject jsonObject, int defaultCoordinateSystemId) 
    { 
     var ob = new MemoryStream(); 

     int? coordinateSystemId; 
     var geoBase = ParseJsonObjectToGeoBase(jsonObject, out coordinateSystemId); 
     geoBase.WellKnownBinary(ob); 

     return new Tuple<byte[], int>(ob.ToArray(), coordinateSystemId.HasValue ? coordinateSystemId.Value : defaultCoordinateSystemId); 
    } 

    /// <summary> 
    /// Write a well-known binary object to JSON. 
    /// </summary> 
    /// <param name="lebr"> 
    /// The little-endian binary reader. 
    /// </param> 
    /// <param name="bebr"> 
    /// The big-endian binary reader. 
    /// </param> 
    /// <exception cref="ArgumentException"> 
    /// Unexpected well-known binary. 
    /// </exception> 
    /// <returns> 
    /// The <see cref="JObject"/> for the given binary data. 
    /// </returns> 
    private static JObject WriteObject(BinaryReader lebr, BinaryReader bebr) 
    { 
     var jsonObject = new JObject(); 
     var br = lebr.ReadByte() == 0 ? bebr : lebr; 
     int gtype = br.ReadInt32(); 
     string objTypeName; 
     if (!WkbTypes.TryGetValue(gtype, out objTypeName)) 
     { 
      throw new ArgumentException(
      string.Format(
      "Unsupported type {0}. Supported types: {1}", 
      gtype, 
      string.Join(", ", WkbTypes.Select(kv => string.Format("({0}, {1}", kv.Key, kv.Value))))); 
     } 

     jsonObject.Add("type", objTypeName); 

     if (gtype == GeometryCollectionWkb) 
     { 
      var array = new JArray(); 
      int count = br.ReadInt32(); 
      for (int i = 0; i < count; ++i) 
      { 
       array.Add(WriteObject(lebr, bebr)); 
      } 

      jsonObject.Add("geometries", array); 
     } 
     else 
     { 
      var array = new JArray(); 
      switch (gtype) 
      { 
      case PointWkb: 
       array.Add(br.ReadDouble()); 
       array.Add(br.ReadDouble()); 
       break; 
      case LineStringWkb: 
       foreach (var a in WriteLine(br)) 
       { 
        array.Add(a); 
       } 

       break; 
      case PolygonWkb: 
       foreach (var a in WritePolygon(br)) 
       { 
        array.Add(a); 
       } 

       break; 
      case MultiPointWkb: 
       int pointCount = br.ReadInt32(); 
       for (int i = 0; i < pointCount; ++i) 
       { 
        br = lebr.ReadByte() == 0 ? bebr : lebr; 
        gtype = br.ReadInt32(); 
        if (gtype != PointWkb) 
        { 
         throw new ArgumentException(
         string.Format("Expected a type of 1, got {0}", gtype), 
         "lebr"); 
        } 

        array.Add(new JArray { br.ReadDouble(), br.ReadDouble() }); 
       } 

       break; 
      case MultiLineStringWkb: 
       int lineCount = br.ReadInt32(); 
       for (int i = 0; i < lineCount; ++i) 
       { 
        br = lebr.ReadByte() == 0 ? bebr : lebr; 
        gtype = br.ReadInt32(); 
        if (gtype != LineStringWkb) 
        { 
         throw new ArgumentException(
         string.Format("Expected a type of 2, got {0}", gtype), 
         "lebr"); 
        } 

        var lineArray = new JArray(); 
        foreach (var a in WriteLine(br)) 
        { 
         lineArray.Add(a); 
        } 

        array.Add(lineArray); 
       } 

       break; 
      case MultiPolygonWkb: 
       int polygonCount = br.ReadInt32(); 
       for (int i = 0; i < polygonCount; ++i) 
       { 
        br = lebr.ReadByte() == 0 ? bebr : lebr; 
        gtype = br.ReadInt32(); 
        if (gtype != PolygonWkb) 
        { 
         throw new ArgumentException(
         string.Format("Expected a type of 3, got {0}", gtype), 
         "lebr"); 
        } 

        var polygonArray = new JArray(); 
        foreach (var a in WritePolygon(br)) 
        { 
         polygonArray.Add(a); 
        } 

        array.Add(polygonArray); 
       } 

       break; 
      default: 
       throw new ArgumentException(string.Format("Unsupported geo-type {0}", gtype), "lebr"); 
      } 

      jsonObject.Add("coordinates", array); 
     } 

     return jsonObject; 
    } 

    /// <summary> 
    /// Write a JSON polygon from well-known binary. 
    /// </summary> 
    /// <param name="br"> 
    /// Read from this. 
    /// </param> 
    /// <returns> 
    /// The <see cref="JArray"/> enumerable for the polygon. 
    /// </returns> 
    private static IEnumerable<JArray> WritePolygon(BinaryReader br) 
    { 
     var ret = new List<JArray>(); 
     int ringCount = br.ReadInt32(); 
     for (int ri = 0; ri < ringCount; ++ri) 
     { 
      var array = new JArray(); 
      foreach (var a in WriteLine(br)) 
      { 
       array.Add(a); 
      } 

      ret.Add(array); 
     } 

     return ret; 
    } 

    /// <summary> 
    /// Write a JSON line from well-known binary. 
    /// </summary> 
    /// <param name="br"> 
    /// Read from this. 
    /// </param> 
    /// <returns> 
    /// The <see cref="JArray"/> enumerable for the line. 
    /// </returns> 
    private static IEnumerable<JArray> WriteLine(BinaryReader br) 
    { 
     var ret = new List<JArray>(); 
     int count = br.ReadInt32() * 2; 
     for (int i = 0; i < count; i += 2) 
     { 
      var array = new JArray { br.ReadDouble(), br.ReadDouble() }; 
      ret.Add(array); 
     } 

     return ret; 
    } 

    /// <summary> 
    /// Create a <see cref="DbGeography"/> or <see cref="DbGeometry"/> from <paramref name="jsonObject"/>. 
    /// </summary> 
    /// <param name="jsonObject"> 
    /// The JSON object. 
    /// </param> 
    /// <param name="objectType"> 
    /// The object type. 
    /// </param> 
    /// <returns> 
    /// The <see cref="DbGeography"/> or <see cref="DbGeometry"/> 
    /// </returns> 
    /// <exception cref="ArgumentException"> 
    /// <paramref name="objectType"/> is not a <see cref="DbGeography"/> or <see cref="DbGeometry"/>. 
    /// </exception> 
    private static object CreateDbGeo(JObject jsonObject, Type objectType) 
    { 
     Func<Tuple<byte[], int>, object> returnValue; 
     int defaultCoordinateSystemId; 
     if (typeof(DbGeography).IsAssignableFrom(objectType)) 
     { 
      returnValue = x => (object)DbGeography.FromBinary(x.Item1, x.Item2); 
      defaultCoordinateSystemId = DbGeography.DefaultCoordinateSystemId; 
     } 
     else if (typeof(DbGeometry).IsAssignableFrom(objectType)) 
     { 
      returnValue = x => (object)DbGeometry.FromBinary(x.Item1, x.Item2); 
      defaultCoordinateSystemId = DbGeometry.DefaultCoordinateSystemId; 
     } 
     else 
     { 
      throw new ArgumentException(string.Format("Expected a DbGeography or DbGeometry objectType. Got {0}", objectType.CSharpName()), "objectType"); 
     } 

     return jsonObject.Type == JTokenType.Null || jsonObject.Type == JTokenType.None ? null : returnValue(GetWellKnownBinary(jsonObject, defaultCoordinateSystemId)); 
    } 

    /// <summary> 
    /// A <see cref="BinaryReader"/> that expects byte-reversed numeric values. 
    /// </summary> 
    public class ReverseEndianBinaryReader : BinaryReader 
    { 
     /// <summary> 
     /// Initializes a new instance of the <see cref="ReverseEndianBinaryReader"/> class. 
     /// </summary> 
     /// <param name="stream"> 
     /// The stream. 
     /// </param> 
     public ReverseEndianBinaryReader(Stream stream) 
     : base(stream) 
     { 
     } 

     /// <inheritdoc/> 
     public override short ReadInt16() 
     { 
      return BitConverter.ToInt16(this.ReadBytes(2).Reverse().ToArray(), 0); 
     } 

     /// <inheritdoc/> 
     public override int ReadInt32() 
     { 
      return BitConverter.ToInt32(this.ReadBytes(4).Reverse().ToArray(), 0); 
     } 

     /// <inheritdoc/> 
     public override long ReadInt64() 
     { 
      return BitConverter.ToInt64(this.ReadBytes(8).Reverse().ToArray(), 0); 
     } 

     /// <inheritdoc/> 
     public override ushort ReadUInt16() 
     { 
      return BitConverter.ToUInt16(this.ReadBytes(2).Reverse().ToArray(), 0); 
     } 

     /// <inheritdoc/> 
     public override uint ReadUInt32() 
     { 
      return BitConverter.ToUInt32(this.ReadBytes(4).Reverse().ToArray(), 0); 
     } 

     /// <inheritdoc/> 
     public override ulong ReadUInt64() 
     { 
      return BitConverter.ToUInt64(this.ReadBytes(8).Reverse().ToArray(), 0); 
     } 

     /// <inheritdoc/> 
     public override float ReadSingle() 
     { 
      return BitConverter.ToSingle(this.ReadBytes(4).Reverse().ToArray(), 0); 
     } 

     /// <inheritdoc/> 
     public override double ReadDouble() 
     { 
      return BitConverter.ToDouble(this.ReadBytes(8).Reverse().ToArray(), 0); 
     } 
    } 

    /// <summary> 
    /// Base class for the types that know how to parse JSON and write well-known binary. 
    /// </summary> 
    public abstract class GeoBase 
    { 
     /// <summary> 
     /// The point well-known bytes descriptor. 
     /// </summary> 
     protected static readonly byte[] PointWkbs = BitConverter.GetBytes(PointWkb); 

     /// <summary> 
     /// The line-string well-known bytes descriptor. 
     /// </summary> 
     protected static readonly byte[] LineStringWkbs = BitConverter.GetBytes(LineStringWkb); 

     /// <summary> 
     /// The polygon well-known bytes descriptor. 
     /// </summary> 
     protected static readonly byte[] PolygonWkbs = BitConverter.GetBytes(PolygonWkb); 

     /// <summary> 
     /// The multi-point well-known bytes descriptor. 
     /// </summary> 
     protected static readonly byte[] MultiPointWkbs = BitConverter.GetBytes(MultiPointWkb); 

     /// <summary> 
     /// The multi-line-string well-known bytes descriptor. 
     /// </summary> 
     protected static readonly byte[] MultiLineStringWkbs = BitConverter.GetBytes(MultiLineStringWkb); 

     /// <summary> 
     /// The multi-polygon well-known bytes descriptor. 
     /// </summary> 
     protected static readonly byte[] MultiPolygonWkbs = BitConverter.GetBytes(MultiPolygonWkb); 

     /// <summary> 
     /// The collection well-known bytes descriptor. 
     /// </summary> 
     protected static readonly byte[] GeometryCollectionWkbs = BitConverter.GetBytes(GeometryCollectionWkb); 

     /// <summary> 
     /// Helper function to parse a <see cref="List{T}"/> of <see cref="Position"/>. 
     /// </summary> 
     /// <param name="array"> 
     /// Get JSON from this. 
     /// </param> 
     /// <returns> 
     /// The parsed JSON. 
     /// </returns> 
     /// <exception cref="ArgumentException"> 
     /// Unexpected JSON. 
     /// </exception> 
     public static List<Position> ParseListPosition(JArray array) 
     { 
      if (array.Cast<JArray>().Any(l => l.Count < 2)) 
      { 
       throw new ArgumentException(
       string.Format(
       "Expected all points to have greater than two points, got {0} with zero and {1} with one", 
       array.Cast<JArray>().Count(l => l.Count == 0), 
       array.Cast<JArray>().Count(l => l.Count == 1)), 
       "array"); 
      } 

      return array.Select(l => new Position { P1 = (double)l[0], P2 = (double)l[1] }).ToList(); 
     } 

     /// <summary> 
     /// Helper function to parse a <see cref="List{T}"/> of <see cref="List{T}"/> of <see cref="Position"/>. 
     /// </summary> 
     /// <param name="array"> 
     /// Get JSON from this. 
     /// </param> 
     /// <returns> 
     /// The parsed JSON. 
     /// </returns> 
     /// <exception cref="ArgumentException"> 
     /// Unexpected JSON. 
     /// </exception> 
     public static List<List<Position>> ParseListListPosition(JArray array) 
     { 
      if (array.Cast<JArray>().Any(r => r.Cast<JArray>().Any(l => l.Count < 2))) 
      { 
       throw new ArgumentException(
       string.Format(
       "Expected all points to have greater than two points, got {0} with zero and {1} with one", 
       array.Cast<JArray>().Sum(r => r.Cast<JArray>().Count(l => l.Count == 0)), 
       array.Cast<JArray>().Sum(r => r.Cast<JArray>().Count(l => l.Count == 1))), 
       "array"); 
      } 

      return array.Select(r => r.Select(l => new Position { P1 = (double)l[0], P2 = (double)l[1] }).ToList()).ToList(); 
     } 

     /// <summary> 
     /// Helper function to parse a <see cref="List{T}"/> of <see cref="List{T}"/> of <see cref="List{T}"/> of <see cref="Position"/>. 
     /// </summary> 
     /// <param name="array"> 
     /// Get JSON from this. 
     /// </param> 
     /// <returns> 
     /// The parsed JSON. 
     /// </returns> 
     /// <exception cref="ArgumentException"> 
     /// Unexpected JSON. 
     /// </exception> 
     public static List<List<List<Position>>> ParseListListListPosition(JArray array) 
     { 
      if (array.Cast<JArray>().Any(p => p.Cast<JArray>().Any(r => r.Cast<JArray>().Any(l => l.Count < 2)))) 
      { 
       throw new ArgumentException(
       string.Format(
       "Expected all points to have greater than two points, got {0} with zero and {1} with one", 
       array.Cast<JArray>().Sum(p => p.Cast<JArray>().Sum(r => r.Cast<JArray>().Count(l => l.Count == 0))), 
       array.Cast<JArray>().Sum(p => p.Cast<JArray>().Sum(r => r.Cast<JArray>().Count(l => l.Count == 1)))), 
       "array"); 
      } 

      return array.Select(p => p.Select(r => r.Select(l => new Position { P1 = (double)l[0], P2 = (double)l[1] }).ToList()).ToList()).ToList(); 
     } 

     /// <summary> 
     /// Write the contents to <paramref name="sout"/> in well-known 
     /// binary format. 
     /// </summary> 
     /// <param name="sout"> 
     /// The stream to write the position to. 
     /// </param> 
     public abstract void WellKnownBinary(Stream sout); 

     /// <summary> 
     /// Parse JSON into the <see cref="GeoBase"/>-derived type. 
     /// </summary> 
     /// <param name="array"> 
     /// Get JSON from this. 
     /// </param> 
     public abstract void ParseJson(JArray array); 
    } 

    /// <summary> 
    /// The position. 
    /// </summary> 
    public class Position : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the first value of the position. 
     /// </summary> 
     public double P1 { get; set; } 

     /// <summary> 
     /// Gets or sets the second value of the position. 
     /// </summary> 
     public double P2 { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream sout) 
     { 
      sout.Write(BitConverter.GetBytes(this.P1), 0, 8); 
      sout.Write(BitConverter.GetBytes(this.P2), 0, 8); 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      if (array.Count < 2) 
      { 
       throw new ArgumentException(string.Format("Expected at least 2 points for a position, got {0}", array.Count), "array"); 
      } 

      this.P1 = (double)array[0]; 
      this.P2 = (double)array[1]; 
     } 
    } 

    // ReSharper disable RedundantNameQualifier 

    /// <summary> 
    /// The point. 
    /// </summary> 
    public class Point : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the position. 
     /// </summary> 
     public Position Position { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream sout) 
     { 
      sout.WriteByte(BitConverter.IsLittleEndian ? (byte)1 : (byte)0); 
      sout.Write(GeoBase.PointWkbs, 0, 4); 
      this.Position.WellKnownBinary(sout); 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      this.Position = new Position(); 
      this.Position.ParseJson(array); 
     } 
    } 

    /// <summary> 
    /// The line string. 
    /// </summary> 
    public class LineString : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the points. 
     /// </summary> 
     public List<Point> Points { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream sout) 
     { 
      sout.WriteByte(BitConverter.IsLittleEndian ? (byte)1 : (byte)0); 
      sout.Write(GeoBase.LineStringWkbs, 0, 4); 
      sout.Write(BitConverter.GetBytes(this.Points.Count), 0, 4); 
      foreach (var point in this.Points) 
      { 
       point.Position.WellKnownBinary(sout); 
      } 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      if (array.Cast<JArray>().Any(l => l.Count < 2)) 
      { 
       throw new ArgumentException(
       string.Format(
       "Expected all points to have greater than two points, got {0} with zero and {1} with one", 
       array.Cast<JArray>().Count(l => l.Count == 0), 
       array.Cast<JArray>().Count(l => l.Count == 1)), 
       "array"); 
      } 

      this.Points = array.Cast<JArray>().Select(l => new Point { Position = new Position { P1 = (double)l[0], P2 = (double)l[1] } }).ToList(); 
     } 
    } 

    /// <summary> 
    /// The polygon. 
    /// </summary> 
    public class Polygon : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the rings. 
     /// </summary> 
     public List<List<Position>> Rings { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream sout) 
     { 
      sout.WriteByte(BitConverter.IsLittleEndian ? (byte)1 : (byte)0); 
      sout.Write(GeoBase.PolygonWkbs, 0, 4); 
      sout.Write(BitConverter.GetBytes(this.Rings.Count), 0, 4); 
      foreach (var ring in this.Rings) 
      { 
       sout.Write(BitConverter.GetBytes(ring.Count), 0, 4); 
       foreach (var position in ring) 
       { 
        position.WellKnownBinary(sout); 
       } 
      } 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      this.Rings = GeoBase.ParseListListPosition(array); 
     } 
    } 

    /// <summary> 
    /// The multi-point. 
    /// </summary> 
    public class MultiPoint : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the points. 
     /// </summary> 
     public List<Position> Points { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream sout) 
     { 
      byte order = BitConverter.IsLittleEndian ? (byte)1 : (byte)0; 
      sout.WriteByte(order); 
      sout.Write(GeoBase.MultiPointWkbs, 0, 4); 
      sout.Write(BitConverter.GetBytes(this.Points.Count), 0, 4); 
      foreach (var point in this.Points) 
      { 
       sout.WriteByte(order); 
       sout.Write(GeoBase.PointWkbs, 0, 4); // Point 
       point.WellKnownBinary(sout); 
      } 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      this.Points = GeoBase.ParseListPosition(array); 
     } 
    } 

    /// <summary> 
    /// The multi-line. 
    /// </summary> 
    public class MultiLineString : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the line strings. 
     /// </summary> 
     public List<List<Position>> LineStrings { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream sout) 
     { 
      byte order = BitConverter.IsLittleEndian ? (byte)1 : (byte)0; 
      sout.WriteByte(order); 
      // ReSharper disable once RedundantNameQualifier 
      sout.Write(GeoBase.MultiLineStringWkbs, 0, 4); 
      sout.Write(BitConverter.GetBytes(this.LineStrings.Count), 0, 4); 
      foreach (var lineString in this.LineStrings) 
      { 
       sout.WriteByte(order); 
       sout.Write(GeoBase.LineStringWkbs, 0, 4); 
       sout.Write(BitConverter.GetBytes(lineString.Count), 0, 4); 
       foreach (var position in lineString) 
       { 
        position.WellKnownBinary(sout); 
       } 
      } 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      this.LineStrings = GeoBase.ParseListListPosition(array); 
     } 
    } 

    /// <summary> 
    /// The multi-polygon. 
    /// </summary> 
    public class MultiPolygon : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the polygons. 
     /// </summary> 
     public List<List<List<Position>>> Polygons { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream sout) 
     { 
      byte order = BitConverter.IsLittleEndian ? (byte)1 : (byte)0; 
      sout.WriteByte(order); 
      sout.Write(GeoBase.MultiPolygonWkbs, 0, 4); 
      sout.Write(BitConverter.GetBytes(this.Polygons.Count), 0, 4); 
      foreach (var polygon in this.Polygons) 
      { 
       sout.WriteByte(order); 
       sout.Write(GeoBase.PolygonWkbs, 0, 4); 
       sout.Write(BitConverter.GetBytes(polygon.Count), 0, 4); 
       foreach (var ring in polygon) 
       { 
        sout.Write(BitConverter.GetBytes(ring.Count), 0, 4); 
        foreach (var position in ring) 
        { 
         position.WellKnownBinary(sout); 
        } 
       } 
      } 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      this.Polygons = GeoBase.ParseListListListPosition(array); 
     } 
    } 

    /// <summary> 
    /// The <see cref="GeoBase"/> collection. 
    /// </summary> 
    public class Collection : GeoBase 
    { 
     /// <summary> 
     /// Gets or sets the entries. 
     /// </summary> 
     public List<GeoBase> Entries { get; set; } 

     /// <inheritdoc/> 
     public override void WellKnownBinary(Stream o) 
     { 
      o.WriteByte(BitConverter.IsLittleEndian ? (byte)1 : (byte)0); 
      o.Write(GeoBase.GeometryCollectionWkbs, 0, 4); 
      o.Write(BitConverter.GetBytes(this.Entries.Count), 0, 4); 
      foreach (var entry in this.Entries) 
      { 
       entry.WellKnownBinary(o); 
      } 
     } 

     /// <inheritdoc/> 
     public override void ParseJson(JArray array) 
     { 
      this.Entries = new List<GeoBase>(); 
      foreach (var elem in array) 
      { 
       if (elem.Type != JTokenType.Object) 
       { 
        throw new ArgumentException(
        string.Format("Expected object elements of the collection array, got {0}", elem.Type), 
        "array"); 
       } 

       int? dummyCoordinateSystem; 
       this.Entries.Add(DbGeographyGeoJsonConverter.ParseJsonObjectToGeoBase((JObject)elem, out dummyCoordinateSystem)); 
      } 
     } 
    } 

    // ReSharper restore RedundantNameQualifier 
} 

Answer 2

GeoJSON.Net使用完整的GeoJson標準實現。