Thanks to a comment on our facebook page: Due to the conflict in state finances in the U,S and A gesocientists are affected: data providers like the USGS and their websites like landcover.org and others are unavailable!
We have already introduced cartoDB which is a platform for storing, administering and visualizing spatial data. One straight feature of cartoDB is the usage of GeoJSON for exporting their tables. In this tutorial I’ll document a working example on consuming this layer with leaflet. But first we will start with the easy part of creating the table in cartoDB.