  A new method of shower-image analysis is presented which appears very
powerful as applied to those Cherenkov Imaging Telescopes with very high
definition imaging capability. It provides hadron rejection on the basis of a
single cut on the image shape, and simultaneously determines the energy of the
electromagnetic shower and the position of the shower axis with respect to the
detector. The source location is also reconstructed for each individual
gamma-ray shower, even with one single telescope, so for a point source the
hadron rejection can be further improved. As an example, this new method is
applied to data from the CAT (Cherenkov Array at Themis) imaging telescope,
which has been operational since Autumn, 1996.
