Contained within the 4th Edition (1974) of the Atlas of Canada is a set of three maps. The first two maps show imports and exports for 1964. Tonnage and commodities are denoted on the maps by means of superimposed pie charts for selected ports. A supplementary text accompanies each of these maps, providing data on tons of cargo imported by sea as well as value of imports by all means of transport for 1964. The third map shows locations of ports in Western Canada handling more than 5000 tons. Pie charts are superimposed on the map and show whether the tonnage was loaded, unloaded, from foreign ports or from other Canadian ports.