Why are almost all modern subway maps geographically incorrect and completely distorted?

A subway map is a diagram of connections

A street map answers, “Where is this place?” A subway map is built to answer a different question: “Which line gets me there, and where do I change trains?” To make that answer readable, designers often distort the city’s shape. Lines may be straightened, bends simplified, and stations spaced more evenly than they are in real life.

The key information is usually topology: which stations connect, which lines serve them, and where a transfer is possible. Topology means the pattern of connections, not the precise distances or angles between places. A diagram can preserve that pattern while moving stations around on the page.

Why accuracy can make a map harder to use

On a geographically exact map, a dense downtown can bunch many stations and intersecting lines into a small area, while long outer routes take up much more space. Labels collide, transfer points become difficult to pick out, and a line’s overall shape can be hard to follow. If the map instead uses a small set of angles and regular spacing, the eye can trace a route and spot changes more quickly.

That simplified geometry is a design tradeoff, not a mistake. A map may stretch a short central segment, compress a long outer one, or show a curved route as a neat sequence of straight segments. The distortion gives crowded information room to breathe, though it also means the map cannot reliably show how far apart stations are or which direction a train travels across the real city.

What the diagram leaves out

This is why subway diagrams work best for planning a ride, not judging walking distance or choosing a street-level meeting point. A station that looks close to another may be separated by a long walk, and the drawn angle between lines may not match their actual direction. Riders who need those details can consult a street map or a map with geographic scale.

The useful trick is to read a subway map as a network, not a miniature city: follow the connections for the route, then use geography for the distance and location.