  We present an experimental procedure for obtaining the conduction channels of
low-dimensional conductors based on shot noise measurements. The transmission
coefficient for each channel is determined numerically from the measured
conductance and Fano factor. The channel analysis is demonstrated for atomic
contacts of Ag, Au, Al and Pt, showing their channel evolution as a function of
conductance and mechanical elongation. This approach can be readily applied to
map the conduction channels in a wide range of nanoscale conductors under
different conditions.
