On the Use and Limitations of Trend Surface Models

A lthough the technique of trend surface mapping has been developed in the main by geologists and geophysicists, its use has now diffused into a number of other fields including regional science, botany, meteorology, and geography. It would be wrong to be unduly critical of the pioneer applications of any technique, even where errors have been made, for there are few guidelines to help such explorers. On the other hand it is felt that trend surface methods are sufficiently well estab-lishd in geography for there to be a need for a more critical appraisal of the method, especially in view of some careless or even erroneous applications that have been made recently by geographers. This paper will highlight what are considered to be some of the more important limitations of trend surface models, and will point to one or two specifically geographical problems.