Is there an open source "Pokemon Go" type geolocation gps map?

I was wonder if anyone has seen an open source project like this. The map is very basic and does not support zooming out very far. I don't want to do all that work if it already exists. It would probably have to use away3d.

If you haven't played the game it's basically a GPS navigator like tomtom without the directions. You go where ever.

A 2d version would also be acceptable.

The map tiles have to be open source and hosted on my server.