OS maps show physical and human features as symbols. This makes the maps easier to read. Each OS map has a key to show what the symbols mean. Large-scale maps - 1:1,250, 1:2,500 and 1:10,000.

Features appear smaller on the map. This may be used to show larger areas or regions. Four-figure grid references locate ... to show height and gradient. On OS maps they are shown as thin orange ...