Scaling properties in highly anisotropic systems

Scaling of the conductances and the finite-size localization lengths is generalized to anisotropic systems and tested in two-dimensional systems. Scaling functions of isotropic systems are recovered once the dimension of the system in each direction is chosen to be proportional to the localization length. It is also shown that the geometric mean of the localization lengths is a function of the geometric mean of the conductivities. The ratio of the localization lengths is proportional to the square root of the ratio of the conductivities, which in turn is proportional to the anisotropy strength $t,$ in the weak scattering limit.