In this study two aerial photograph interpretation methods, visual and digital classification, were used for the aquatic macrophyte mapping of a eutrophic study lake in the Finnish Lake District. The study indicated that aerial photograph interpretation is a useful monitoring method of aquatic macrophytes in lakes dominated by helophytes and nymphaeids. Visual classification produced the taxonomically best, mainly species-specific information, while in digital classification aquatic macrophytes were categorized according to life forms or phenotypes and the coverage of vegetation stands. The overall classification accuracies were defined to be 81% for visual and 83% for digital classification. In the sense of time used, digital classification was 3.5 times more effective than visual classification. With the aid of both the methods the abundance of different macrophyte categories in hectares were produced and the areas for the corresponding categories were rather similar. It is also poss...