Views and viewpoints explained

Each stakeholder in a project has his own point of view. In architecture these are called viewpoints. From a viewpoint a view on the architecture can be created.

There is no such thing as one architecture view. I have seen many projects that show me a usually large picture with many lines and boxes stating: "This is our architecture". This is nonsense. At best they are showing one view on the architecture. And sometimes not even that.

Usually the picture is meant for communicating the architecture to a certain group of stakeholders like project members, end users or management. The point here is that there is no such thing as "the architecture picture". There are only architectural views. And views are created from viewpoints.

Viewpoints can be seen as places from where an observer is located ("the viewpoint is that I am on top of a mountain"), and views are what can be seen from that viewpoint ("and from here I see the villages in the valley"). Other viewpoints ("I am standing in the valley") provide different views ("I see snow on top of the mountains").

The same goes for architectural views and viewpoints, where the observers are the stakeholders of the project. The viewpoint of end users of a system is completely different than the viewpoint of a system manager. And this viewpoint is completely different from that of a purchaser, a business manager or a business partner. They all look at the same system, but their views are radically different. For example:

• For an end user the system consists of user screens with buttons, reports, and other functionalities. They want the architecture of a system expressed as mocked-up screenshots. This gives them an impression of the system that is built and how it addresses their concerns.
• For a systems manager the system consists of software that is installed on hardware. The hardware and software must be configured. His view on the architecture will for instance be an overview of what software runs on what server and which network connections are active. He sees the configuration tool as a user interface.
• The purchase department sees the system as a bill of material for hardware and a set of licenses for software to be purchased.

Of course other stakeholders can have completely different views. The architect must express the architecture in various views to be able to communicate it to the various stakeholders. Not all views must be created at the start of the project- the view can be created when the need arises. It is important to remember that multiple views are needed to describe the architecture of a system.

This entry was posted on Donderdag 28 Maart 2013