A geometry-independent approach to a unified description of intensity corrections factors for the two most common surface scattering geometries is presented. Simple analytical formulas relate the representations of the Lorentz factor, polarization factor, area factor, and rod interception factor in a surface reference frame to the actual diffractometer circles. An analytical formula for the area correction for very large exit angles, as can be achieved on modern diffractometers, is derived. A test data set shows that the derived formulas provide a good description of the scattering intensity up to the edge of the Ewald sphere. (C) 2002 American Institute of Physics.