4+1 View Model Taxonomy
SKOS taxonomy of the 4+1 Architectural View Model (Kruchten, 1995). Defines five viewpoint categories that can be used to classify viewpoints in any custom metamodel. The 4+1 model is language-agnostic — it describes what concerns each view addresses, not which notation to use.
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4+1 Architectural View Model
Classification scheme based on Philippe Kruchten's 4+1 View Model (IEEE Software, 1995). Organizes architecture descriptions into four concurrent views (Logical, Process, Development, Physical) plus a unifying Scenarios view that validates and illustrates the others.
Logical View
Design View
Addresses the functional requirements — what the system provides to end users. Describes the key abstractions (objects, classes, packages) and their relationships. Concerned with decomposition, encapsulation, and interface design.
In UML: class diagrams, object diagrams, package diagrams. In ArchiMate: Application layer elements (ApplicationComponent, ApplicationService, ApplicationInterface, DataObject). In C4: Component diagrams.
Domain model, service interfaces, module decomposition
Process View
Concurrency View
Addresses non-functional requirements — concurrency, distribution, performance, scalability, fault tolerance. Describes the runtime behavior: processes, threads, synchronization, and communication mechanisms.
In UML: activity diagrams, sequence diagrams, state machine diagrams. In ArchiMate: Triggering and Flow relationships, ApplicationProcess, ApplicationEvent. In BPMN: full process models with gateways and events.
Message flows between services, event-driven choreography, thread pools
Development View
Implementation View
Addresses the organization of the software in its development environment. Describes modules, packages, layers, subsystems, and their dependencies. Concerned with build structure, team allocation, and reuse.
In UML: component diagrams, package diagrams. In C4: Container diagrams (deployable units and their technology choices). In Backstage: Component and System catalog entries with ownership.
Microservice boundaries, shared libraries, monorepo structure
Physical View
Deployment View
Addresses the mapping of software to hardware — topology, deployment, communication, and infrastructure. Describes nodes, networks, and the allocation of processes and components to physical or virtual resources.
In UML: deployment diagrams. In ArchiMate: Technology layer (Node, Device, SystemSoftware, CommunicationNetwork) with Assignment relationships. In C4: Deployment diagrams.
Kubernetes cluster topology, cloud region layout, network zones
Scenarios View
+1 View
Use Case View
The unifying view — a set of key scenarios (use cases) that drive and validate the architecture. Each scenario traces through the other four views, showing how elements from the Logical, Process, Development, and Physical views collaborate to fulfill a user goal.
In UML: use case diagrams, sequence diagrams showing end-to-end scenarios. In ArchiMate: motivation elements (Stakeholder, Goal, Requirement) linked to application and business elements. In C4: System Context diagrams showing user interactions.
User places an order — traces from UI through services, queues, database, to deployment