Zurich's Duplicate Image Problem: What Happens Next and the Key Decisions Ahead

Zurich's municipal administration is sitting on a problem that has grown quietly for years: thousands of duplicate digital images scattered across city-managed servers, planning portals and public archive systems, with no unified policy yet in place to resolve it. The issue came to a head this spring when the Stadtarchiv Zürich flagged the scale of redundancy in its digitisation pipeline, putting pressure on civic IT teams to act before the next budget cycle closes in autumn 2026.

The timing matters. The city is mid-way through an ambitious digitisation of historical planning documents tied to the Arealentwicklung Leutschenbach project in the north of the city, and administrators at Stadthaus Zürich have acknowledged internally that duplicated image files are inflating storage costs and causing version-control errors in shared planning workflows. With housing supply under acute strain — the Wohnungsnot crisis has pushed vacancy rates in the city below one percent — any friction in the digital planning process has real-world consequences for approval timelines on new residential developments.

What the problem actually looks like

Duplicate image records accumulate in two main ways. Scanning operators working across multiple departments — the Stadtarchiv on Alfred-Escher-Strasse, the Amt für Städtebau on Lindenhofstrasse — independently digitise the same source documents without a shared deduplication protocol. Separately, the migration of older file systems onto newer cloud infrastructure has produced layer upon layer of copied assets, some dating back to early digitisation drives in the 2000s. The result is a sprawling, inconsistently tagged image library that costs money to store and creates legal and administrative uncertainty about which version of a document is canonical.

ETH Zürich's Information Science and Engineering group has been developing hash-based deduplication tools for cultural heritage collections, and discussions are underway about whether that methodology could be adapted for municipal use. The university sits less than two kilometres from the main city archive on Neumarkt, making institutional collaboration logistically straightforward. No formal partnership has been announced, but city IT procurement records reviewed by The Daily Zurich indicate that an external tender for a deduplication audit was issued in May 2026, with responses due by 31 July.

The decisions that will define the outcome

Three choices now sit on the desk of city administrators. First, whether to consolidate image management under a single authority — most likely the Stadtarchiv — or to let each department retain ownership of its own assets under a shared tagging standard. Centralisation is faster to implement but politically sensitive in a city where direct-democracy traditions make departmental autonomy a genuine cultural value, not just an administrative preference.

Second, the city must decide what to do with duplicates once identified. Deletion is not automatic: Swiss archival law imposes retention obligations on records that may have legal or historical value, meaning a legal review must precede any bulk purge. That review alone could take six months under the city's current staffing levels.

Third, and most consequentially for residents, the city needs to set a policy on public access during any transition. Planning documents for developments in Zürich West and the Altstetten district are currently accessible via the online portal Geoportal ZH. If a deduplication process temporarily restricts access to contested files — a realistic scenario during system migration — that affects the ability of neighbourhood associations and individual citizens to participate in the planning consultations that Swiss law guarantees them.

The tender deadline of 31 July sets a natural first checkpoint. If a vendor is selected by September, a deduplication audit could be completed before the end of the 2026 fiscal year, giving the Gemeinderat a concrete evidence base when it debates the 2027 digital infrastructure budget. If the process slips, the city faces another year of accumulating redundancy — and the Leutschenbach project, already under timeline pressure, will be the most visible casualty. Residents and neighbourhood groups in Kreis 11 watching that development would be well advised to monitor the tender outcome and ask, at the next public consultation, exactly which image of the plan they are being shown is the one that counts.