AN ANALYSIS OF ALTERNATIVE CLASSIFICATION SCHEMES FOR MEDICAL ATLAS MAPPING

Most national disease atlases adopt a classification scheme based on e ither the percentile distribution of rates or on the national mean. Al though these schemes have a direct interpretation, they are based on t he univariate statistical distribution of rates and not on their spati al distribution, and distort the underlying spatial autocorrelation in the data. If the purpose of the maps is to represent spatial patterns , alternative classification schemes might be more appropriate. This r esearch proposes an alternative classification method that maximises s patial similarity among contiguous units in the same class interval. T he method has been illustrated using selected data from the German Can cer Atlas published in 1984. Copyright (C) 1996 Elsevier Science Ltd