p2d2Public-Public
Data-DNA

What is p2d2? ​

p2d2 can be understood as middleware between citizens' data and the open data of their public administrations.

The application enables the integration, quality assurance, and collaborative use of data from both spheres – citizen data and administrative data. Metaphorically, the two spheres can be understood as the two strands of a DNA molecule. The base pairing in the DNA metaphor then corresponds to the synchronicity of individual data objects.

The project begins with geodata, as its visualizability and recognizability provide accessible entry points into this complex topic. However, the underlying architecture is deliberately not limited to geodata: The Data-DNA metaphor encompasses the totality of data from citizens on one hand and the data of their public administrations on the other.

p2d2 synchronizes open government data with public data platforms such as OpenStreetMap, WikiData, and other community-driven data sources. To manage the spatial data, an open-source and OGC-compliant spatial data infrastructure (SDI) is an integral component of the project.

• Web Site: https://www.data-dna.eu
• Develeopment-Version of the web site for testing: https://dev.data-dna.eu
• Releeases and Releaseplanning: https://release.data-dna.eu
• Documentation Web Site: https://doc.data-dna.eu

Core Principles ​

• 🔓 Open Source: Fully open source under GPLv3
• 🌐 Standards-compliant: OGC-compliant SDI following GDI-DE principles
• 👥 Community-driven: Citizens as active data collectors
• 🔄 Bidirectional: Synchronization between administration and the public

Technology Stack ​

• Frontend: AstroJS, OpenLayers, TypeScript
• Backend: PostgreSQL/PostGIS, GeoServer, MapProxy
• Infrastructure: Proxmox VE, OPNsense, GitLab CI/CD
• Standards: WFS, WFS-T, WMS, WMTS, TMS, GeoJSON

Repositories ​

• Origin: gitlab.opencode.de/OC000028072444/p2d2
• Mirror: gitlab.opencode.de/unbox-cologne/p2d2/p2d2-mirror
• Hub: github.com/Peter-Koenig/p2d2-hub

AI Notice ​

• This work and documentation were created with AI tool support
• Especially in the documentation, there are sections where the AI overshot its mark and hallucinated content
• To provide an overview, a QS/QM (Quality Assurance/Quality Management) system was installed that allows quality parameters to be specified for each page, so that the reliability of the page can be estimated. Over time, all pages should be reviewed and evaluated
• Earlier Markdown documents from the project directory were integrated on November 17, 2025
• Earlier implementation protocols, e.g. for Proxmox, MapServer or Geoserver setup, still need to be evaluated and then replace the "flowery-vague" descriptions of many documentation pages
• The system went into operation on November 17, 2025