  We address quantum metrology in critical spin chains with anisotropy and
Dzyaloshinskii-Moriya (DM) interaction, and show how local and quasi-local
measurements may be exploited to characterize global properties of the systems.
In particular, we evaluate the classical (magnetization) and quantum Fisher
information of the relevant parameters for the density matrix of a single spin
and that of a pair of spins ranging from nearest to sixth-nearest neighbors, to
the limiting case of very distant spins. Our results allow us to elucidate the
role of the different parameters and to individuate the optimal working regimes
for the precise characterization of the system, also clarifying the effects of
correlations on the estimation precision.
