Zurich's Digital Archive Problem: The Key Decisions Ahead on Duplicate Image Replacement

Zurich's public institutions are sitting on a growing problem. Tens of thousands of duplicate images — accumulated across municipal databases, cultural archives, and urban planning systems — are clogging digital infrastructure and inflating storage costs, and a series of decisions expected before the end of 2026 will determine how aggressively the city moves to fix it.

The issue is not unique to Zurich, but it has particular urgency here. The city's push toward full digital administration, accelerated by a canton-wide e-government mandate adopted in 2023, means that legacy file systems originally built without deduplication protocols are now feeding directly into public-facing services. Redundant image files slow retrieval times, complicate version control, and — critically for a city that prizes transparency — make it harder for residents to trust that official records are accurate and current.

Where the Backlog Is Concentrated

The pressure is sharpest at two institutions. The Stadtarchiv Zürich, based on Neumarkt in the Altstadt, manages historical photographic collections that were digitised in multiple waves between 2008 and 2021. Because each digitisation round used different file naming conventions, thousands of images exist in two or three near-identical versions with no automated flag to identify the original. Staff have been working through the backlog manually, but the archive's own project documentation, published on the city's open-data portal, puts the unresolved duplicate rate at roughly 12 percent of the total photographic holdings as of late 2025.

Zurich's urban planning department, the Amt für Städtebau, faces a parallel challenge. Aerial survey images and building permit photographs taken across districts including Altstetten and Schwamendingen are stored across at least three separate systems that were never fully integrated. When planners query records for a rezoning review — something happening with increasing frequency as the city battles its Wohnungsnot housing shortage — they routinely encounter conflicting image versions with no clear audit trail indicating which file was most recently verified.

ETH Zurich's Chair of Information Architecture has been studying the municipal case as part of a broader European research programme on public-sector data governance. The institution is expected to publish findings in the fourth quarter of 2026, and city IT officials have been briefed on the preliminary work, according to the project's publicly listed stakeholder register.

The Decisions That Cannot Wait

Three choices are now in front of city administrators, and the window for making them is narrowing. First, Zurich's Stadtrat must decide by September whether to fund a centralised deduplication platform — estimated in a procurement consultation document circulated in May 2026 at between CHF 1.4 million and CHF 2.1 million depending on scope — or to continue with institution-by-institution manual review. The manual approach costs less upfront but has already taken four years without resolving the core problem.

Second, the city needs to settle on a metadata standard. The European standard Dublin Core and the Swiss-specific eCH-0160 archival format are both on the table. eCH-0160, developed under the guidance of the federal e-Government standards body, is already used by the Staatsarchiv des Kantons Zürich on Winterthurerstrasse, which gives it a natural advantage for interoperability. A decision either way must come before any new platform is procured, because the choice of standard dictates the software architecture.

Third, and most politically sensitive, is the question of public access during any transition period. Zurich's direct democracy culture means citizens regularly submit formal requests — under the Öffentlichkeitsgesetz — for municipal image records to support neighbourhood planning challenges, heritage objections, and infrastructure disputes. Any extended period where duplicate files create ambiguous results in the public archive risks generating legal challenges and eroding confidence in the process.

The Stadtrat's IT and culture committees are scheduled to hold a joint session on the matter in late August. Whatever framework emerges there will feed into the 2027 budget cycle, meaning the autumn deliberations in the Gemeinderat are the last realistic checkpoint before costs escalate further. Residents and civic groups who want to shape the outcome have until mid-August to submit formal input through the city's consultation portal at stadt-zuerich.ch.