How Zurich's Digital Archive Crisis Reached Breaking Point: The Duplicate Image Problem Explained

Zurich's municipal administration is sitting on a digital storage problem it can no longer ignore. Across city departments — from the Stadtarchiv on Neumarkt to the communications offices of Stadtentwicklung Zürich — hundreds of thousands of duplicate image files have accumulated over more than a decade, consuming server capacity, inflating licensing costs, and slowing down the retrieval systems that civil servants rely on daily.

The issue did not appear overnight. It is the product of decisions made, or avoided, during the rapid digitisation push of the 2010s, when individual departments adopted their own content management systems with little coordination from the centre. By the time the city's IT governance body, Amt für Informatik (AFI), began pushing for unified digital asset management in 2022, the duplication was already deeply embedded.

A Fragmented System Built Up Over Years

The structural roots go back to roughly 2008, when the city began digitising its photographic heritage in earnest. The Stadtarchiv Zürich, housed at Neumarkt 4 in the Niederdorf quarter, took the lead on historical material. But contemporary communications photography — event coverage, infrastructure documentation, planning visualisations — was managed separately by each of the city's around 30 Dienstabteilungen, or service departments. Without a shared taxonomy or a central repository, the same image routinely ended up saved under different filenames, in different formats, and on different servers.

ETH Zurich's Information Science group has published research pointing to exactly this pattern in large institutional archives: when metadata standards are absent at the point of ingestion, deduplication costs multiply exponentially with time. By one widely cited estimate in digital records management literature, the cost of correcting poor data quality is between five and ten times higher when addressed retrospectively than when standards are applied at creation. Zurich's experience fits that model closely.

The practical consequences are visible in day-to-day administration. Staff at the Stadthaus on Stadthausquai — the main civic building on the west bank of the Limmat — regularly encounter retrieval delays when searching the city's internal image libraries. A search for photographs of, say, the Hardbrücke renovation returns dozens of near-identical variants with no clear master record flagged. Time spent reconciling those results is time not spent on substantive work.

What Changed — and What Comes Next

The trigger for the current push toward resolution was a city council budget review completed in the spring of 2025. Councillors scrutinising the AFI's infrastructure line identified cloud storage expenditure that had grown by more than 30 percent in three years, with duplicate media files identified as a significant contributing factor. The AFI was instructed to report back with a remediation plan by the first quarter of 2026.

That plan, now under internal review, centres on deploying automated deduplication software across the city's primary data nodes, combined with a retroactive metadata tagging exercise. The Stadtarchiv is expected to serve as the pilot site, given its relatively well-structured existing catalogue. If the pilot meets its targets — reducing verified duplicates in a defined collection by at least 60 percent within six months — the approach would roll out city-wide.

For residents, the immediate impact is indirect but real. The Wohnungsnot crisis has pushed housing planning data — including architectural imagery, site surveys, and planning consultation photographs — into heavy use by departments working on new developments in areas like Altstetten and Oerlikon. When that data is disorganised, decisions slow down. Streamlining the archive is, in that sense, part of the same efficiency conversation the city has been having about its ability to deliver on housing commitments.

Organisations submitting public records requests under the cantonal Öffentlichkeitsgesetz, the Swiss freedom-of-information framework, have also run into the duplication problem: requests sometimes return bloated batches of visually identical files, raising questions about whether the substantive records have actually been provided or simply buried in noise.

The AFI is expected to present its pilot findings to the city executive before the end of September 2026. Digital records specialists and civic technology advocates watching the process will be looking for evidence that the governance structures — not just the software — have genuinely changed. Without mandatory metadata standards enforced at the point of upload, the consensus view among information professionals is that the same accumulation problem will simply repeat itself within a decade.