  Topological insulators are physically distinguishable from normal insulators
only near edges and defects, while in the bulk there is no clear signature to
their topological order. In this work we show that the Z index of topological
insulators and the Z index of the integer quantum Hall effect manifest
themselves locally. We do so by providing an algorithm for determining these
indices from a local equal time ground-state correlation function at any
convenient boundary conditions. Our procedure is unaffected by the presence of
disorder and can be naturally generalized to include weak interactions. The
locality of these topological indices implies bulk-edge correspondence theorem.
