A new method of classification for Landsat data using the 'watershed' algorithm

Abstract Many methods of classifying satellite imagery have been suggested. Most of the accepted methods, either supervised or unsupervised, are founded on the assumption that the radiance values of a particular ground cover type can be characterized by some probability distribution having a central value(s) and a range parameter(s). This assumption is rarely, if ever, tenable and hence the methods must produce unnecessarily high rates of misclassification. Thus there is a need for an approach which avoids this type of assumption. Pattern recognition techniques, e.g. the ‘watershed’ algorithm, can be used to divide up the radiance-frequency domain, provided the radiance values can be reduced to 2 dimensions. These methods do not presuppose any ‘shape’ for the radiance-frequency distributions and therefore provide an unbiased aid to the interpretation of satellite imagery.