Classical U(1) Lattice Gauge Theory in D=2
  Under the hypothesis of no topological structure below a certain scale, we prove that any U(1) lattice configuration corresponds to a classical U(1) gauge field with zero local field strength; i.e. any local representative of the pullback connection one-form is a pure gauge and the local curvature two-form is thus identical zero. The topological information is completely carried by the chart transitions. To each such U(1) lattice configuration we assign a Chern number, which generally depends on the reconstruction of the bundle and is only unique under certain restrictions. 
H. Gausterer, M. Sammer