  We derive physical parameters of galaxies from their observed spectrum, using
MOPED, the optimized data compression algorithm of Heavens, Jimenez & Lahav
2000. Here we concentrate on parametrising galaxy properties, and apply the
method to the NGC galaxies in Kennicutt's spectral atlas. We focus on deriving
the star formation history, metallicity and dust content of galaxies. The
method is very fast, taking a few seconds of CPU time to estimate 17
parameters, and so specially suited to study of large data sets, such as the
Anglo-Australian 2 degree field galaxy survey and the Sloan Digital Sky Survey.
Without the power of MOPED, the recovery of star formation histories in these
surveys would be impractical. In the Kennicutt atlas, we find that for the
spheroidals a small recent burst of star formation is required to provide the
best fit to the spectrum. There is clearly a need for theoretical stellar
atmospheric models with spectral resolution better than 1\AA if we are to
extract all the rich information that large redshift surveys contain in their
galaxy spectra.
