  The effect of strain in graphene is usually modeled by a pseudo-magnetic
vector potential which is, however, derived in the limit of small strain. In
realistic cases deviations are expected in view of graphene's very high strain
tolerance, which can be up to 25%. Here we investigate the pseudo-magnetic
field generated by a Gaussian bump and we show that it exhibits significant
differences with numerical tight-binding results. Furthermore, we calculate the
electronic states in the strained region for a hexagon shaped flake with
armchair edges. We find that the six-fold symmetry of the wave functions inside
the Gaussian bump is directly related to the different effect of strain along
the fundamental directions of graphene: zigzag and armchair. Low energy
electrons are strongly confined in the armchair directions and are localized on
the carbon atoms of a single sublattice.
