  Graphene on a dielectric substrate exhibits spatial doping inhomogeneities,
forming electron-hole puddles. Understanding and controlling the latter is of
crucial importance for unraveling many of graphene's fundamental properties at
the Dirac point. Here we show the coexistence and correlation of charge puddles
and topographic ripples in graphene decoupled from the metallic substrate it
was grown on. The analysis of interferences of Dirac fermion-like electrons
yields a linear dispersion relation, indicating that graphene on a metal can
recover its intrinsic electronic properties.
