  The increasing cosmic ray statistics collected by present experiments and the
future prospects with new large arrays demand accurate calculations of the
extensive air shower parameters. The energy of the primary particle is
estimated by ground arrays fitting a lateral distribution function (LDF) to the
particle densities at a given observing level. However, the lack of appropriate
parameterization for these distributions, able to reproduce the data collected
from all arrival directions, makes it difficult the experimental analysis.
Starting from analytical LDF for vertical showers we study the atmospheric
depth dependence of the shower parameters, which is necessary to obtain the
corresponding particle density distributions for inclined showers. In our
approach both geometrical and atmospheric attenuation effects producing a
lateral asymmetry in non-vertical showers are included. The resulting electron
and muon LDF fit very well the Monte Carlo simulated data at all zenith angles.
