It can be easy to assume that maps are objective: that the world is out there, and that a good map is one that represents it accurately. But that's not true. Any square kilometre of the planet can be described in an infinite number of ways: in terms of its natural features, its weather, its socio-economic profile, or what you can buy in the shops there.
Traditionally, the interests reflected in maps have been those of states and their armies, because they were the ones who did the map-making, and the primary use of many such maps was military. (If you had the better maps, you stood a good chance of winning the battle. The logo of Britain's Ordnance Survey still includes a visual reference to the 18th-century War Department.) Now, the power is shifting.
"Every map," the cartography curator Lucy Fellowes once said, "is someone's way of getting you to look at the world his or her way."