How Zurich's Digital Archives Became Buried in Duplicate Images — and What It Cost

Zurich's municipal administration is sitting on a problem that grew in plain sight. Across dozens of city departments — from the Stadtarchiv on Alfred-Escher-Strasse to the communications teams embedded in Rathaus offices — the same photographs, graphics and scanned documents have been saved, renamed and re-uploaded so many times that administrators who work with these systems estimate the problem spans years of compounding digital clutter. No single failure caused it. The situation is the result of accumulated habits, legacy software, and a digitisation push that moved faster than any governance framework could keep pace with.

The timing matters because Zurich is now mid-way through its Smart City Strategie, a programme the city council formally adopted to modernise infrastructure and public services through coordinated data management. Duplicate image files are not a glamorous policy problem, but they sit at the centre of something larger: whether the city's digital backbone is actually fit for the transparency and efficiency that direct democracy demands. Citizens who file requests under the cantonal information law expect clean, searchable records. What they sometimes encounter instead are document repositories bloated with near-identical files, making retrieval slower and audit trails harder to follow.

How the Duplicates Accumulated

The roots go back to the early 2010s, when individual Zurich departments began their own digitisation projects without a shared file management standard. The Stadtarchiv, which holds records going back centuries and is housed near Enge, developed its own cataloguing conventions. The Amt für Städtebau, responsible for planning documents across neighbourhoods from Altstetten to Oerlikon, used different software. The communications unit at the Stadthaus on Stadthausquai operated on a third system entirely. When files moved between these silos — which they did constantly, for reports, press releases, planning applications — the standard practice was to save a new copy rather than link to an existing one.

Cloud migration made things worse before it made them better. When several departments shifted to shared platforms between 2018 and 2022, bulk uploads from old local servers brought the duplicate problem with them, multiplied across new storage environments. Industry benchmarks from the document management sector suggest that organisations without deduplication policies typically find between 25 and 40 percent of stored image files are redundant copies — a figure that, applied to a city the administrative size of Zurich, represents a non-trivial annual cost in cloud storage contracts alone.

ETH Zurich's information science faculty has published research on precisely this kind of institutional data entropy, noting that public-sector organisations face a structural disadvantage: unlike private companies with a financial incentive to trim storage costs aggressively, city departments historically operated with fixed IT budgets that absorbed inefficiency rather than eliminating it. Swiss cloud storage rates, while competitive within Europe, still mean that unnecessary duplication across a large municipal operation adds up to tens of thousands of francs annually in avoidable expenditure.

The Push Toward a Fix

The corrective work is already under way in patches. The Stadtarchiv has been piloting an automated deduplication tool since late 2024, cross-referencing file hashes to identify identical images regardless of their filenames. The Amt für Informatik, which coordinates IT services for the city administration from its offices in Zürich-West, has been rolling out a unified digital asset management protocol intended to establish a single authoritative file library that departments link to rather than copy from.

The practical implications extend beyond storage budgets. When journalists, researchers, or citizens request historical images under the cantonal Öffentlichkeitsgesetz, staff currently have to manually check multiple repositories to confirm they have located the canonical version of a document rather than a later duplicate that may carry different metadata. Standardising that process is one explicit goal of the current reform effort.

Completing the deduplication sweep across all major city departments is projected to take until at least the end of 2027, according to the Smart City programme's public documentation. For residents and businesses dealing with the Baurekursgericht or other permit-heavy processes in neighbourhoods like Wiedikon and Schwamendingen, the practical payoff will be faster document retrieval and fewer administrative delays. Getting there requires the kind of unglamorous coordination work that rarely makes headlines — but determines whether the smart city vision functions in practice.