utymap
Highly customizable library for procedural world generation
... shows how to import map data from a file. Please note, that import and rendering logic depends on maps rules which means you cannot use arbitrary mapcss with the arbitrary data format. Elevation scene shows how elevation support works. Please note, as the scene loads multiple tiles at once, mapzen server might reject some of the requests. Also, first-time loading takes time, just wait a little bit and restart the scene again.