Compare: A FORTRAN IV program for the quantitative comparison of polynomial trend surfaces

Abstract The method of polynomial trend surface analysis is used widely in the earth sciences. Many applications deal with surfaces fitted to a single variable in a particular area, but some are concerned with multiple variables, or a single variable measured in different areas. For these situations, quantitative assessments of the similarity between fitted surfaces can be obtained with a number of simple statistics, which are reviewed. A FORTRAN IV program to calculate polynomial trend surfaces up to third-order (cubic) for two data sets, and derive comparison measures, is described; and its operation is illustrated with a worked example.