Zurich's Duplicate Image Problem: The Key Decisions That Will Shape What Comes Next

Zurich's civic data managers are facing a reckoning. Across municipal departments—from the Stadtarchiv on Neumarkt to the digital infrastructure teams at the Stadthaus on Stadthausquai—a sprawling inventory of duplicate images has accumulated in public databases, internal document systems, and the city's open-data portal. The question of how to identify, remove, or replace those duplicates is no longer a back-office afterthought. It has become an active policy debate, with decisions expected before the end of the third quarter of 2026.

The issue matters now because Zurich is mid-stream in a broader digital governance overhaul tied to the city's Smart City Strategy, which the Stadtrat formally adopted and has been implementing since 2021. Migrating legacy records into new cloud-based infrastructure has exposed just how fragmented image storage became during years of decentralised department management. Redundant files inflate storage costs, complicate search and retrieval, and—critically—create legal ambiguity around which version of a document image is the authoritative one.

Where the Backlog Sits and Who Is Responsible

The Stadtarchiv, housed in the Haus zum Rech building on Neumarkt, holds the longest institutional memory on this problem. Archivists there have been working since at least 2024 to catalogue digitised historical photographs and planning documents, some of which were scanned multiple times by different departments without coordination. ETH Zurich's Chair of Information Science has been in preliminary dialogue with the city about applying automated duplicate-detection algorithms to the archive's holdings, though no formal contract has been announced.

Separately, the cantonal administration at the Regierungsgebäude on Neumühlequai manages its own image repositories for land registry, infrastructure permits, and public health records. The two systems—city and canton—do not currently communicate automatically. That gap means a photograph submitted as part of a building permit application in Aussersihl could exist in three separate databases simultaneously: the applicant's submission, the city planning office's intake copy, and a cantonal land-use archive scan.

Storage is not cheap at institutional scale. Enterprise cloud storage for Swiss public-sector entities typically runs between CHF 0.02 and CHF 0.05 per gigabyte per month under current procurement frameworks, and when multiplied across tens of millions of archived image files, the cumulative cost is significant. A 2025 audit by the city's Finanzkontrolle—Zurich's independent financial oversight body—flagged digital storage inefficiency as a line item worth scrutiny, though the audit did not publish a specific figure for image duplication specifically.

The Decisions Ahead This Autumn

Three choices will define how the city proceeds. First, administrators must decide whether to adopt a centralised deduplication tool or allow departments to manage their own cleanup. Centralisation is faster and cheaper, but it requires agreement on which copy is canonical—a question that is less technical than it sounds, because different departments may have annotated or processed the same source image differently.

Second, the city must resolve whether citizen-facing platforms—including the open-data portal at data.stadt-zuerich.ch—should surface duplicate images at all, or whether the portal's next update, expected in early 2027, will include automated filtering. Open-data advocates in Zurich, including civil society groups active around the Rote Fabrik cultural centre in Wollishalden, have argued that transparency requires preserving version histories rather than silently deleting older copies.

Third, there is a procurement question. The city is evaluating whether to build deduplication capability into existing contracts with its current IT providers or to run a new tender under Swiss public procurement law, which mandates open competition for contracts above CHF 230,000.

None of these decisions is purely technical. Each carries implications for transparency, archival integrity, and public spending—values that Zurich voters, who regularly exercise direct democratic rights on city budgets through Volksabstimmungen, take seriously. A proposal touching digital infrastructure spending could plausibly reach a municipal ballot if the Gemeinderat requests a public referendum, adding another layer of accountability to what began as a filing problem. The Stadtrat is expected to present a position paper by September 2026.