Methods are equivalent to the forces that act upon every adjacent pair of dominoes and contribute to a more significant overall process. Data can therefore be organised in a relatively unstructured way, without penalty, in terms of access to information. OO further permits models like the traffic light to be encapsulated, allowing the application programmer to focus on how the model behaves, rather than on how it works. It is sufficient for a user to know how to ask for information, rather than to know how to derive it, and a request can be as simple as selecting an item in a menu, clicking on a graphic in a map, or using the keypad alongside enumerated map content. The simplicity of the user interaction is non-restrictive of the complexity of the subsequent processing.
Different countries have different approaches to traffic control.
OO provides additional flexibility, called polymorphism, to hide distinct behaviours in a single data model - a user request is handled differently depending on the class of the feature selected. While several GIS providers have embraced OO, they have done so in a variety of ways. Some use it to build dynamic in-memory structures, while others have implemented persistent data stores. The fat-server architecture is ideal for mobile services, because data management is centrally controlled. Map Generalisation and dynamic presentation is now achieved automatically by implementing the draw operation as a method.