  Quantum Hall edge states are the paradigmatic example of the bulk-boundary
correspondence. They are prone to intricate reconstructions calling for their
detailed investigation at high spatial resolution. Here, we map quantum Hall
edge states of monolayer graphene at a magnetic field of 7 T with scanning
tunneling microscopy. The graphene sample features a gate-tunable lateral
interface between areas of different filling factor. We compare the results
with detailed tight-binding calculations quantitatively accounting for the
perturbation by the tip-induced quantum dot. We find that the edge state
pattern is mapped with little perturbation by adequate choice of gate voltage.
We observe extended compressible regions, the antinodal structure of edge
states and their meandering along the lateral interface.
