The increasing importance of the polar regions, and in particular the increasing use of polar waters by shipping, has led to publication in recent years of a number of ice atlases. These compilations attempt to summarize in cartographic form existing knowledge of the seasonal distribution of floating ice (mainly sea ice, but icebergs also are important in certain areas). The atlases seek to present a summary which is based on the greatest possible number of observations within a given period, and from which deductions may be drawn as to the future. They are therefore not to be confused with ice charts of another sort, which show only actual situations at particular times—although the two sorts may be used to complement each other. A summary of the currently available atlases and their characteristics may be helpful.