Good architecture is a legible and communicable map

A good architecture must function as a map for navigating a system. The actual system is the territory that exists in real life, and a good architecture must do the work of compressing the information in the system into a legible and communicable map.

A map must first be legible. This means that the map must not over-compress the information of the system. It must also exist in a form that can be understood by those who will implement a system, whether that is in a diagram, a document, a software representation, or some other form. Like the map of a territory, a good architecture must be usable as a form of navigation for those who wish to build or maintain the system.

A map must also be convertible to other maps. This means that the map should support conversions to new architectures, as required by those who may want to update the system.