prize7-1, Exercise 1: Reading a map you know

Model answer (example: the London Underground map; check the details):

Shows: lines, stations and interchanges, in colour-coded routes.
Leaves out: true distances, the real shape of the lines above ground, streets and most landmarks apart from the River Thames.
Scale: none in the usual sense. Distances between stations are adjusted to give a clear picture, so the scale varies across the map.
Symbols: coloured lines for routes, ticks and circles for stations and interchanges, a blue band for the river.
Orientation: roughly north at the top, but with lines straightened to angles of 45 and 90 degrees.

Takeaway: this map is a diagram that serves one purpose, finding a route by train, and it would mislead anyone using it to walk between stations. A different purpose would need a different map (see Chapter 8).