Abstract The hydrolittoral areas of the regulated Lake Luodonjärvi (63° 45′N lat., 22°50′E long.) on the eastern coast of the Gulf of Bothnia were studied by means of Landsat satellite imagery. It proved possible to detect spectral differences between different water areas. Seventeen aquatic complexes or types were classified separately on the basis of changes in water characteristics and depth, bottom quality and vegetational succession. The vegetation in summer 1983 was recorded in this way and reviewed against previous mappings in order to illustrate the multitemporal aspects of Landsat studies. Landsat classification could be used equally effectively in large area control, offering as it does the possibility of mapping the distribution of certain types of coastal environment over large areas by means of reflected radiation intensities.