Topological map
In cartography and geology, a topological map is a type of diagram that has been simplified so that only vital information remains and unnecessary detail has been removed. These maps lack scale, and distance and direction are subject to change and variation, but the relationship between points is maintained. A good example is the tube map of the London Underground or the map for the New York City Subway.
The name topological map is derived from topology, the branch of mathematics that studies the properties of objects that do not change as the object is deformed, much as the tube map retains useful information despite bearing little resemblance to the actual layout of the underground system.
