  From deflections in galactic and extragalactic magnetic fields energy
dependent structures in the arrival directions of ultra-high energy cosmic rays
(UHECR) are expected. We propose to characterize these structures by the
strength of collimation of energy along the principal axes in selected regions
in the sky. While the strength of collimation are indicators of anisotropy in
the arrival distribution of UHECR, the orientation of the principal system
holds information about the direction of the deflections of UHECR. We discuss
the method and present expected limits on the strength of deflection and
density of sources using simulated scenarios of UHECR proton propagation.
