  We present EZ (Easy redshift), a tool we have developed within the VVDS
project to help in redshift measurement from otpical spectra. EZ has been
designed with large spectroscopic surveys in mind, and in its development
particular care has been given to the reliability of the results obtained in an
automatic and unsupervised mode. Nevertheless, the possibility of running it
interactively has been preserved, and a graphical user interface for results
inspection has been designed. EZ has been successfully used within the VVDS
project, as well as the zCosmos one. In this paper we describe its architecture
and the algorithms used, and evaluate its performances both on simulated and
real data. EZ is an open source program, freely downloadable from
http://cosmos.iasf-milano.inaf.it/pandora.
