LatLngAlt as default

[workingDog]

I'm starting to write a simple app to convert Kml to GeoJSON using the play-geojson library.
See https://github.com/workingDog/kmlToGeojson.

Given that the WGS84 as a CRS references the ellipsoid,
would it make sense to have the LatLng be a LatLngAlt with the altitude as an option as I did in my app?
At the moment the altitude cannot be set with just LatLng.

PS
The SphericalMercator in the readme.md shows Ints not Doubles and the installation instruction shows "com.typesafe.play.extras" %% "play-geojson" % "1.2.0"

[jroper]

I think it would make sense to add a LatLngAlt type to play-geojson, but still keep LatLng around. In practice, many people simply don't care about altitude when working with play-geojson, so keeping a very simple LatLng around I think makes sense - for me, working with leaflet on the client side which also defines a LatLng type, it feels more natural to work with LatLng on the client and on the server. Note that the design of play-geojson makes no one CRS better than another, a user simply selects which one they want to use using the type system.

One other change that we probably should do to play-geojson is support reading LatLng from a 3 coordinate array, currently I think it will fail. It should simply drop the altitude if it encounters it. Or, we should at very least produce a meaningful error message, currently the user will just get a match error.

[workingDog]

Ok, grab the code for LatLngAlt and add
case Seq(lng, lat, alt) => LatLngAlt(lat, lng)
to LatLng -> object Wgs84Format __.read.

[workingDog]

correction, add case Seq(lng, lat, alt) => LatLng(lat, lng)