using System;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        var deSerialized = JsonConvert.DeserializeObject<MyModel>("{\"myName\":\"My Name\",\"myPolygon\":{\"type\":\"Polygon\",\"coordinates\":[[[-100.0,45.0],[-98.0,45.0],[-99.0,46.0],[-100.0,45.0]]]}}");

        Console.WriteLine("myName: " + deSerialized.myName);

        Console.WriteLine("myPolygon type: " + deSerialized.myPolygon?.type);

        Console.WriteLine("myPolygon coordinates:");

        foreach (var point in deSerialized.myPolygon.coordinates[0])

        {

            Console.WriteLine($" ({point[0]}, {point[1]})");

        }

    }

}

​

public class MyModel

{

    public string myName { get; set; }

​

    [JsonConverter(typeof(MyPolygonConverter))]

    public Polygon myPolygon { get; set; }

}

​

public class Polygon

{

    public string type { get; set; }

    public double[][][] coordinates { get; set; }

}

​

public class MyPolygonConverter : JsonConverter<Polygon>

{

    public override Polygon ReadJson(JsonReader reader, Type objectType, Polygon existingValue, bool hasExistingValue, JsonSerializer serializer)

    {

        JObject jo = JObject.Load(reader);

        Polygon poly = new Polygon();

        poly.type = (string)jo["type"];

        poly.coordinates = jo["coordinates"].ToObject<double[][][]>(serializer);

        return poly;

    }

    public override bool CanWrite => false;

    public override void WriteJson(JsonWriter writer, Polygon polygon, JsonSerializer serializer)

    {

        throw new NotImplementedException();

    }

}