ABSTRACT
The consideration of spatial scale has a long history in geomorphology, particularly with reference to the mapping and classification of landforms. In soil science, the need to map ‘homogeneous’ units has led to enquiries which seek to define the amount of variability accommodated within such units. Two approaches to the estimation of spatial variability are evident in hydrology and pedology. Following the review of P.H.T. Beckett and R. Webster, the variability of soil characteristics in space has been defined almost exclusively by the coefficient of variability, estimated for pedons, soil series or some larger spatial unit. On a single site, i.e. on a smaller scale than that defined by between-site variances, the distance–variability relationship may be examined as a spatial series, since the marked particles were introduced systematically along a line. R.M. Summer describes one such experiment involving the distance–variability relationship in the context of a single geomorphic process.
