  A chaotic attractor is usually characterised by its multifractal spectrum
which gives a geometric measure of its complexity. Here we present a
characterisation using a minimal set of independant parameters which are
uniquely determined by the underlying process that generates the attractor. The
method maps the f(alpha) spectrum of a chaotic attractor onto that of a general
two scale Cantor measure. We show that the mapping can be done for a large
number of chaotic systems. In order to implement this procedure, we also
propose a generalisation of the standard equations for two scale Cantor set in
one dimension to that in higher dimensions. Another interesting result we have
obtained both theoretically and numerically is that, the f(alpha)
characterisation gives information only upto two scales, even when the
underlying process generating the multifractal involves more than two scales.
