What is PETRA?
PETRA (Provinciale EnTerprise Referentie Architectuur, the provincial enterprise reference architecture) is the shared reference architecture of the Dutch provinces: a set of reference models and theme architectures that a province uses to design its business functions, processes, data and applications in a coherent and reusable way. PETRA is a formal daughter of NORA and is maintained by the Platform provincie-architecten (PPA), a professional group in which every province takes part with at least one architect. The current PETRA was published in November 2021 on its own wiki; the older version remains online only as an archive and no longer has a leading role.
PETRA gives twelve provinces one language and one set of building blocks, so no province has to draw its own architecture from scratch.
🎯 Why do provinces need their own reference architecture?
Dutch provinces have a set of responsibilities that differs from those of municipalities, water authorities or central government. The Interprovincial Consultative Body (IPO) summarises them as seven core tasks: sustainable spatial development including water management; environment, energy and climate; a vital countryside and nature; regional accessibility and regional public transport; the regional economy; cultural infrastructure and heritage; and the quality of public administration. A generic government architecture only partly covers those tasks.
| Aim | What it means in practice |
|---|---|
| Common language | One set of concepts and one business function model, so architects from different provinces understand each other’s models |
| Reuse | A province starts from reference models instead of a blank page, which especially helps smaller architecture teams |
| Alignment with national frameworks | Through NORA, PETRA connects to national principles, standards and shared facilities |
| Grip on national programmes | Theme architectures translate programmes such as the Environment and Planning Act (Omgevingswet) and the Single Digital Gateway into provincial processes and applications |
🧱 How is PETRA structured?
PETRA follows NORA’s five-layer model. The emphasis is on the organisation and information layers; technical architecture is deliberately not worked out in reference models.
| NORA layer | Content in PETRA |
|---|---|
| Foundations (Grondslagen) | Laws and regulations that apply to provinces; provincial architecture principles (this item is currently paused on the roadmap) |
| Organisation | Interprovincial business function model, business process model and business object model (business architecture) |
| Information | Business object model and a metamodel for the enterprise data model (information architecture) |
| Application | An application function model, on the backlog and possibly linked to the reference components of the GEMMA software catalogue (application architecture) |
| Network | No reference models; PETRA does not work out technical architectures |
All models are published as an ArchiMate model in a semantic wiki (MediaWiki with Semantic MediaWiki). Architects can look up the context of every element and its relationships with other elements, so they can use the models as a starting point for their own architecture models.
The business function model
The interprovincial business function model has three layers:
- Governing functions - five main functions: strategy and governance, policy and planning, change management, improvement management and accountability (governance)
- Primary functions - including interaction, policy, execution (with cabinet affairs as a separate function), decision-making, research and innovation, data management and sustainably accessible records management; the policy functions are aligned with the seven core tasks
- Supporting functions - based on the Dutch SCOPAFIJTH breakdown, extended with procurement and contract management, with information provision and technology merged into a single function
🗺️ Which theme architectures does PETRA contain?
Besides the generic models, PETRA contains theme architectures for national programmes that affect all provinces at the same time.
| Theme | Status | Content |
|---|---|---|
| Environment and Planning Act for provinces | Version 3.00, January 2021, developed in three iterations (2019–2021) | Roles, processes, eight business object models, the application landscape and the link with the national Digital System for the Environment and Planning Act (DSO), treated as a black box; plus sustainable accessibility, privacy and security |
| Single Digital Gateway (SDG) | Version 1.00, first iteration delivered in 2023 | Processes, business objects and information flows for EU Regulation (EU) 2018/1724, which had to be fully applied by 12 December 2023 |
| Data (backlog) | In preparation | Data management, data governance and data architecture |
The Environment and Planning Act entered into force on 1 January 2024. Because the theme architecture covers sources up to January 2021, a province has to compare later changes to the DSO against the model itself.
🔄 How does PETRA relate to NORA, GEMMA, WILMA and MARIJ?
PETRA is one of the sector daughters of NORA. What NORA already covers, such as the five-layer model and the national principles, PETRA adopts; only province-specific topics are worked out separately.
| Architecture | Government layer | Relationship to PETRA |
|---|---|---|
| NORA | Entire government | Parent architecture; provides the five-layer model, principles and standards |
| GEMMA | Municipalities | Sister architecture; overlaps with PETRA on the Environment and Planning Act and through the software catalogue |
| WILMA | Water authorities | Sister architecture; relevant for area-based cooperation and water management |
| MARIJ | Central government | Central government architecture; alignment with central facilities and policy programmes |
For the information domain, PETRA refers to national standards. The metamodel for the enterprise data model combines DAMA-DMBOK with MIM (the Metamodel Informatie Modellering from Geonovum) and distinguishes a conceptual, a logical and a physical level. Provinces also work with domain models such as IMRO for older spatial plans, STOP/TPOD for environmental documents and IMEV for external safety.
🏭 Where does PETRA touch OT?
Provinces manage more physical installations than is often assumed: provincial roads with traffic control installations, movable bridges and locks on provincial waterways, tunnels, monitoring networks for air and groundwater quality, and building services in provincial offices. These systems run on SCADA, PLCs and telemetry and fall under OT.
PETRA itself contains no OT or security model. The business function model covers the execution of asset management tasks, but the technical layer on which bridges and locks are operated is out of scope. A province that wants to connect its IT and OT therefore combines PETRA with other frameworks:
- OT architecture - zones, Purdue levels and interfaces between the office and the control environment
- IEC 62443 - zones and conduits, security levels and requirements for suppliers
- CSIR - the object classification from Rijkswaterstaat and Het Waterschapshuis, which is also usable for provincial bridges and locks
- Network segmentation (segmentation of office and process networks) and secure remote access for maintenance contractors
In addition, the Provincial Executive is the competent authority for the environmental permit of many major-hazard (Brzo) sites. The provincial information landscape therefore also touches process safety and cybersecurity at Seveso sites.
🔐 Which security frameworks apply alongside PETRA?
PETRA does not define its own security standards, but provinces must meet national frameworks:
- BIO - until 2020 provinces had their own baseline (IBI); since then the BIO, now BIO2, has applied to all government layers, explicitly including OT
- Cybersecurity Act - since 15 August 2026 provinces have been essential entities, supervised by the Dutch Authority for Digital Infrastructure (RDI) (see scope of the Cbw)
- Information Security Policy - each province sets out in its own policy who is responsible for IT and OT security
- Security by Design and Privacy by Design - the Environment and Planning Act theme architecture treats privacy and security as a separate aspect alongside the five layers
🔧 How do you use PETRA in practice?
- Start with the business function model - map your own organisation onto the three layers and mark the autonomous tasks your province performs on top of the core tasks.
- Reuse the business objects - use the business object model and the metamodel as the basis for your own data catalogue.
- Use theme architectures as a checklist - when you introduce a new case management system for permits, check that all Environment and Planning Act processes and DSO connections are covered.
- Fill in the technical layer yourself - describe network, OT and security in your own architecture, with BIO2 and IEC 62443 as the normative framework.
- Feed back - share findings and your own elaborations through the PPA, so the next iteration of PETRA improves.
❓ Frequently asked questions
What does the acronym PETRA stand for?
PETRA stands for Provinciale EnTerprise Referentie Architectuur, the provincial enterprise reference architecture. It is the reference architecture of the Dutch provinces and a formal daughter of NORA.
Who maintains PETRA?
PETRA is maintained by the Platform provincie-architecten (PPA), a professional group in which every province takes part with at least one architect. The PPA publishes PETRA on its own wiki and keeps a roadmap of new and planned components.
Is PETRA mandatory for provinces?
PETRA is not a statutory framework but a shared reference model. Provinces use PETRA voluntarily as a starting point, while legal requirements such as BIO2 and the Cybersecurity Act apply independently of it.
What is the difference between PETRA and NORA?
NORA is the reference architecture for the entire Dutch government and provides the five-layer model and the national principles. PETRA builds on it and only works out province-specific topics, such as the interprovincial business function model and the theme architectures for the Environment and Planning Act and the Single Digital Gateway.
Does PETRA cover OT and cybersecurity?
PETRA does not work out the technical and network layer, so it contains no OT or security model. Provinces supplement it with BIO2, IEC 62443 and sector guidelines such as the CSIR for bridges and locks.
In what form is PETRA available?
PETRA is published online as a semantic wiki with ArchiMate models that architects can browse and query element by element. The theme architectures for the Environment and Planning Act and the Single Digital Gateway are also available as PDF documents.
📌 In summary
Since its relaunch in 2021, PETRA has been a living product: the PPA adds models in iterations, from business functions and processes to data models and theme architectures. Its strength lies in the organisation and information layers; every province has to fill in the technical layer and OT itself.
PETRA is the provincial elaboration of NORA: a shared reference model for functions, processes and data, which a province supplements with BIO2, IEC 62443 and its own OT architecture.