Optimal sampling strategies for mapping soil types. I. Distribution of boundary spacings

SUMMARY The pattern of soil types that occur in a region can be described simply in terms of the distributions of spacings between successive soil boundaries and the probabilities of transitions from soil type to soil type. Studies of eight detailed soil maps of England and Wales, representing a very wide range of terrain patterns, showed that in all instances the interboundary spacings measured along sample transects were very satisfactorily described by the gamma distribution. In some instances the shape parameter of the distribution was sensibly 1, so that the simpler negative exponential function fitted the observed distributions well. Transition probability matrices distinguished complex and nondescript soil patterns from the more strongly repetitive ones.