  The passage from angular to spatial correlations, in the case of spatial
clustering length depending on the average distance between nearby objects is
studied. We show that, in a number of cases, the scaling law of angular
correlation amplitudes, which holds for constant spatial clustering length, is
still true also for a luminosity dependent spatial correlation. If the Limber
equation is then naively used to obtain `the' spatial clustering length from
the angular function amplitude, a quantity close to the average object
separation is obtained. The case of cluster clustering is explicitly
considered.
