  Recent advances in gamma-ray cosmic ray, infrared and radio astronomy have
allowed us to develop a significantly better understanding of the galactic
medium properties in the last few years. In this work using the DRAGON code,
that numerically solves the CR propagation equation and calculating gamma-ray
emissivities in a 2-dimensional grid enclosing the Galaxy, we study in a self
consistent manner models for the galactic diffuse gamma-ray emission. Our
models are cross-checked to both the available CR and gamma-ray data. We
address the extend to which dark matter annihilations in the Galaxy can
contribute to the diffuse gamma-ray flux towards different directions on the
sky. Moreover we discuss the impact that astrophysical uncertainties of non DM
nature, have on the derived gamma-ray limits. Such uncertainties are related to
the diffusion properties on the Galaxy, the interstellar gas and the
interstellar radiation field energy densities. Light ~10 GeV dark matter
annihilating dominantly to hadrons is more strongly constrained by gamma-ray
observations towards the inner parts of the Galaxy and influenced the most by
assumptions of the gas distribution; while TeV scale DM annihilating dominantly
to leptons has its tightest constraints from observations towards the galactic
center avoiding the galactic disk plane, with the main astrophysical
uncertainty being the radiation field energy density. In addition, we present a
method of deriving constraints on the dark matter distribution profile from the
diffuse gamma-ray spectra. These results critically depend on the assumed mass
of the dark matter particles and the type of its end annihilation products.
