Using NTS.IO.GeoJSON with ASP.NET Core MVC

ASP.NET Core MVC 3.0 or higher

This is a solution that HarelM and Buzzology contributed.

1. Add Newtonsoft.Json package reference
   <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.0.0" />
2. Add the following code to the ConfigureServices(IServiceCollection) function of your startup class.

services.AddControllers(options => { 
// Prevent the following exception: 'This method does not     support GeometryCollection arguments' 
// See: https://github.com/npgsql/Npgsql.EntityFrameworkCore.PostgreSQL/issues/585 
    options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(Point))); 
    options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(Coordinate))); 
    options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(LineString))); 
    options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(MultiLineString))); 
}).AddNewtonsoftJson(options => { 
    foreach (var converter in NetTopologySuite.IO.GeoJsonSerializer.Create(new GeometryFactory(new PrecisionModel(), 4326)).Converters) { 
        options.SerializerSettings.Converters.Add(converter); 
    } 
}).SetCompatibilityVersion(CompatibilityVersion.Version_3_0);

An example of the code in use can be seen in the IsrealHikingMap repository.

---

ASP.NET Core MVC, pre-3.0

This is how jochenjonc does it in a ASP.Net Core Web Api project, tomek14 contributed.

public class Startup
{
    // ...
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc(options =>
            {
                // Prevent the following exception: 'This method does not support GeometryCollection arguments'
                // See: https://github.com/npgsql/Npgsql.EntityFrameworkCore.PostgreSQL/issues/585
                options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(Point)));
                options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(LineString)));
                options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(MultiLineString)));
                // Addition from user tomek14
                options.ModelMetadataDetailsProviders.Add(new SuppressChildValidationMetadataProvider(typeof(Feature)));
            })
            .AddJsonOptions(options =>
            {
                foreach (var converter in GeoJsonSerializer.Create(new GeometryFactory(new PrecisionModel(), 4326)).Converters)
                {
                    options.SerializerSettings.Converters.Add(converter);
                }
            })
            .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
            // ...
        }
        // ...
    }

Derived from Issue #5