prize7-10, Exercise 1: The six questions applied

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

1. Who made it? Harry Beck, an engineering draughtsman, in 1931, then revised by the Underground's staff and designers over many years.
2. For whom and why? Passengers choosing a route, so the diagram simplifies the network to help them.
3. From what source? The real railway lines and stations, drawn as a diagram, not from a survey of positions.
4. What choices? Lines at 45 and 90 degrees, even station spacing, colours for lines, a simplified river, zones.
5. What does it leave out? True distances and directions, streets, walking times between stations, and many landmarks.
6. How to check? Compare with a geographic map or a walking-time map before walking between stations.

Assessment: trustworthy for connections and order of stations, unreliable for distances and directions. The diagram is a good map for its purpose and a poor one for any other.