Support number type for "Feature.Id" property

As per the RFC:

3.2.  Feature Object
   o  If a Feature has a commonly used identifier, that identifier
      SHOULD be included as a member of the Feature object with the name
      "id", and the value of this member is either a JSON string or
      number.

Would it possible for GeoJSON.Net to support a number value for Feature.Id, in addition to a string value?

[xfischer]

Hi @dalbani and @matt-lethargic !

Could it be possible to say that

• Id is an object property or whatever IEquatable thing
• The writeJson could handle if it is convertible to a numeric type and then serialize it as a numeric type ?

The problem here is that now Id MUST be a string, even if it represents a number. It could be changed to object, and we tell NewtonSoft.Json to serialize it the way it should.

[xfischer]

@matt-lethargic’s PR is neat and works. OK with @dalbani for the downside of getting back a string.

I wish I had more time to test the Issue100 branch, but I don’t ! I don’t know enough pure GeoJSON.Net lib (I’m more in the spatial contribs) but for sure it’s a breaking change. (Imagine someone uses string manipulation on the Id property in its code (like Id.Length), changing Id to object would surely destroy (at least) the planet.