Contained within the 4th Edition (1974) of the Atlas of Canada is a plate that has three maps. The first map that shows the density of roads in Eastern Canada. Density is indicated by a colour code showing areas where roads are less than 1 mile apart, 1 to 2 miles apart and 2 to 4 miles apart. Isolated roads and ferries are also shown. A second map at a scale of 1:20 000 000 is included and shows major highways for all of Canada. A third map, at a scale of 1:35 000 000, shows sources of the data for density of roads.