  The investigation of the static and dynamic structural properties of
colloidal systems relies on techniques capable of atomic resolution in real
space and femtosecond resolution in time. Recently, the cross-correlation
function (CCF) analysis of both X-rays and electron diffraction patterns from
dilute and dense aggregates has demonstrated the ability to retrieve
information on the sample's local order and symmetry. Open questions remain
regarding the role of the beam coherence in the formation of the diffraction
pattern and the properties of the CCF, especially in dense systems. Here, we
simulate the diffraction patterns of dense two-dimensional monodisperse systems
of different symmetries, varying the transverse coherence of the probing wave,
and analyze their CCF. We study samples with different symmetries at different
size scale, as for example, pentamers arranged into a four-fold lattice where
each pentamer is surrounded by triangular lattices, both ordered and
disordered. In such systems, different symmetry modulations are arising in the
CCF at specific scattering vectors. We demonstrate that the amplitude of the
CCF is a fingerprint of the degree of the ordering in the sample and that at
partial transverse coherence, the CCF of a dense sample corresponds to that of
an individual scattering object.
