Zurich's Digital Archives Are Riddled With Duplicate Images — and Officials Say the Cleanup Bill Is Rising

Zurich's public institutions are sitting on a growing digital housekeeping problem. Duplicate images — photographs, scanned documents, and planning visuals stored multiple times across disconnected systems — have accumulated to the point where archive managers at several cantonal bodies are now pressing for coordinated replacement protocols. The issue surfaced publicly this spring when the Canton of Zurich's digital services unit flagged redundant file sets during a broader IT audit, drawing attention from both civic technologists and budget overseers at the Stadthaus on Stadthausquai.

The timing is not coincidental. Switzerland's public sector has spent the past three years migrating paper-heavy records onto cloud infrastructure, a push accelerated after the Federal Council endorsed the country's E-Government Strategy 2024–2027. That rush to digitise — done department by department, without unified metadata standards — created fertile ground for duplication. A single planning photograph from the Schwamendingen tram extension project, for example, might exist in the cantonal spatial planning office, the city transport department, and the public communications archive simultaneously, each copy tagged differently, none flagged as redundant.

What the Experts Are Saying

Archivists and information scientists at ETH Zurich's Chair of Information Architecture have been vocal in internal working groups about the downstream costs. The core argument: duplicate images are not just a storage nuisance. When public portals serve inconsistent or outdated versions of the same official image — say, a rendering of the planned Hardbrücke redevelopment — it erodes document reliability and complicates freedom-of-information requests. Researchers at the university have pointed to perceptual hashing and AI-assisted deduplication as the most practical remediation tools available at scale, though adoption across Swiss cantonal systems remains uneven.

The city's own IT directorate, Organisation und Informatik (OIZ), acknowledged the scope of the problem in a working paper circulated to departmental heads in April 2026. Without citing a specific tally, the document described the redundancy burden as materially affecting storage procurement costs. Zurich spends roughly CHF 85 million annually on IT infrastructure across its core municipal departments, according to the city's 2025 budget report, and storage inefficiencies form a growing line item within that envelope.

Independent digital governance consultants working with Swiss municipalities — several of whom presented at a March 2026 forum hosted by the Swiss Federal Archives in Bern — have argued that the fix requires policy as much as technology. Their position: without a binding cantonal directive requiring departments to check a central image registry before uploading new files, deduplication tools will simply treat symptoms while the underlying process continues generating redundant copies.

Local Programs and What Comes Next

Two Zurich-specific initiatives are now in play. The city's Open Data Zurich portal, maintained by the statistics office on Napfgasse, launched a metadata harmonisation pilot in May 2026 covering geospatial and planning imagery. The goal is to establish a shared unique identifier for each canonical image, making downstream duplication detectable automatically. Separately, the Zentralbibliothek Zürich on Zähringerplatz has been piloting duplicate-detection software across its digitised historical photograph collection since late 2025, with results expected to inform a wider cantonal recommendation later this year.

Officials overseeing these programs have been careful not to overstate progress. The OIZ working paper from April explicitly noted that a city-wide image replacement framework — one that would retire duplicate files and redirect links to a single master copy — would require cross-departmental sign-off and legal review of records-retention obligations under cantonal archiving law.

For residents and researchers who use public data portals, the practical implication is straightforward: search results may still surface multiple versions of the same official document image, and users should cross-reference file dates and source departments until the harmonisation pilot expands. The Open Data Zurich team has published a guidance note on its portal advising exactly that. The metadata pilot is scheduled for formal evaluation in October 2026, with a cantonal recommendation expected before the end of the year.