  Analytical expressions for the distribution of the length of chords
corresponding to the affine invariant measure on the set of chords are given
for convex polygons. These analytical expressions are a computational
improvement over other expressions published in 2011. The correlation function
of convex polygons can be computed from the results obtained in this work,
because it is determined by the distribution of chords.
  An analytical expression for the multi-chord distribution of the length of
chords corresponding to the affine invariant measure on the set of chords is
found for non convex polygons. In addition we give an algorithm to find this
multi-chord distribution which, for many concave polygons, is computationally
more efficient than the said analytical expression. The results also apply to
non simply connected polygons.
