Experiments were carried out to determine the relationship between the accuracy of visual estimates of certain statistical characteristics of maps and a number of factors, such as symbols, colours etc. Maps from the "Atlas Slovenskiy Socialistickey Republiky', 1984 were used in the experiments, carried out by students in the Geographical Faculty of Leningrad University. Several regularities were revealed between the accuracy of visual estimates of information contained in the maps and the symbols and colours used on the maps. -translated by P.Cooke