This report is one of a series of computer program manuals arising from a continuing study of computer applications in the earth and environmental sciences, including geology, geography, geophysics, geochemistry, and environmental engineering. The present paper discusses a method for evaluating to what extent a classification of items defined by a set of measures reflects a rationale rather than errors. A geometrical interpretation is provided of the concepts of systematic and random elements of a classification and of the analytic tools proposed. The methods are illustrated by an application to the analysis of a classification of climatic stations. A listing and description of the computer program used is appended.