  We define Ratner-Marklof-Strombergsson measures. These are probability
measures supported on cut-and-project sets in R^d (d > 1) which are invariant
and ergodic for the action of the groups ASL_d(R) or SL_d(R). We classify the
measures that can arise in terms of algebraic groups and homogeneous dynamics.
Using the classification, we prove analogues of results of Siegel, Weil and
Rogers about a Siegel summation formula and identities and bounds involving
higher moments. We deduce results about asymptotics, with error estimates, of
point-counting and patch-counting for typical cut-and-project sets.
