The Tube map is a diagram, and that is why it works

Before 1931, maps of the London Underground tried to be maps. They put the lines where they ran on the ground, which meant the center of the city, where most of the stations are, turned into a knot, while the suburbs, with far fewer stations, took up most of the sheet.

A draughtsman with a spare weekend

Henry Charles Beck, known as Harry, was a technical draughtsman. He had been working in the signalling department of the Underground Electric Railways of London and had been laid off. After that he redrew the network the way he had drawn circuit diagrams at work: colored lines, only vertical, horizontal and 45 degree angles, and stations spaced evenly along them.

The railway's publicity office turned the design down at first. Beck resubmitted an updated copy, they changed their minds, and a limited trial run followed in 1932. A pocket edition came out in January 1933 and was popular immediately. It was formally adopted that year, and almost every metro map in the world has borrowed from it since.

What it leaves out

The diagram is honest about what it is for. A passenger underground does not see the street, so what matters is the order of the stations and where the lines meet.

But the distances are real, and our own data shows how far the diagram bends them. The coordinates we use for the Central line put Debden and Theydon Bois about 3.2 kilometers apart in a straight line. The two stations at the other end of the scale, Holborn and Chancery Lane, are about 0.4 kilometers apart. On the Tube map they sit at nearly the same spacing. A five-minute walk and a three-kilometer run look like the same hop.

Why we draw a different map

HelloSubway uses real positions on its map because the game is about places. When you type a station name, the train moves to its actual location, and the photo beside the nameplate is of something within walking distance. If you ride the Central line from West Ruislip to Epping, you will see the gaps open up near the end, the way they would from a window.

Neither map is better. Beck's diagram answers "how do I get there", and a geographic map answers "where is that". If you look at both for the same line you learn more than from either one alone.