Re: Converting polygons and multi-polygons to GeoJSON

[xivk]

I usually use this:

private static string ToJson(FeatureCollection featureCollection)

{

var jsonSerializer = new NetTopologySuite.IO.GeoJsonSerializer();

var jsonStream = new StringWriter();

jsonSerializer.Serialize(jsonStream, featureCollection);

var json = jsonStream.ToInvariantString();

return json;

}

Perhaps you can reuse part of this...

On Thursday, September 1, 2016 at 2:35:21 PM UTC+2, Fenix Fyre wrote:

Can anyone provide me with some assistance I need to convert some polygons and multi-polygons stored in a database to GeoJSON so that I can display them on a Google Map?

I have created the code below which currently returns an empty JSON string:

 public ContentResult Boundaries()
        {
            ViewIt_V2Entities viewItV2 = new ViewIt_V2Entities();
            var geometryQuery = (from shapes in viewItV2.UTLA_Shapes
                select shapes.Geometry).ToList();
            GeometryConverter geometryConverter = new GeometryConverter();
            StringBuilder sb = new StringBuilder();
            StringWriter sw = new StringWriter(sb);
            JsonWriter jsonWriter = new JsonTextWriter(sw);
            JsonSerializer jsonSerializer = new GeoJsonSerializer();
            foreach (var geometry in geometryQuery)
            {
                geometryConverter.WriteJson(jsonWriter, geometry, jsonSerializer);
            }
            return Content(sb.ToString(), "application/json");
        }

How to do I go about converting the polygons and multi-polygons to GeoJSON using the NetTopologySuite?

Thanks,

Simon 

[Fenix Fyre]

Thanks xivk for the prompt reply was wondering how you go about converting DbGeometry to a FeatureCollection have tried to use a foreach loop to iterate through the geometryQuery List and add each polygon to a Feature but am presented with the error cannot resolve constructor.

Any ideas?

[Ben Abelshausen]

No sorry, I guess creating a new feature collection and adding the geometries as features? Have never worked with DbGeometry or geometryQuery...

Met vriendelijke groeten,
Best regards,

Ben Abelshausen

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