Many applications exist that deal with relations, between people in a social network, between functions in a software system, or between cities in a transportation network. Typically, such relations are not static, but they are changing more or less frequently over time. This means the social contacts of people may differ from time to time, the function calls may change if new components are implemented, or routes may be blocked due to traffic jams or bad weather conditions.
Maps for public transport as busses, subways or trains are part of our daily live. It is self-evident for most of us to read them and we expect them to be designed in a way that we can plan our journeys easily. But who cares about the usability and the design? And how can we be guaranteed that the map design invokes an accurate action by the passengers? Design experts and visualization researchers are working closely together to produce readable and effective map designs.