Berlin Leads Europe on Duplicate Image Replacement, but Amsterdam and Vienna Are Closing the Gap

Berlin's Senate Department for Urban Development confirmed earlier this year that its citywide geodata portal, FIS-Broker, had accumulated more than 340,000 duplicate or superseded image files across planning documents submitted between 2018 and 2025. The problem is not unique to Berlin, but the city's response — a phased automated deduplication programme launched in January 2026 — has drawn attention from municipal data offices across Europe.

Why does this matter now? Cities across Europe are racing to digitise decades of analogue planning records, building permits, and public infrastructure photographs as part of broader smart-city and open-data initiatives. That rush creates a predictable side effect: servers fill with near-identical images, outdated aerial surveys get re-uploaded under different file names, and public portals slow to a crawl. In Berlin, where the SPD-led coalition has staked part of its digital governance reputation on the Berliner Open Data Strategy, redundant assets are more than a storage nuisance — they're a transparency problem.

The deduplication work is being coordinated through the Kompetenzzentrum Geodateninfrastruktur at Alexanderplatz, working alongside the Zentraler IT-Dienstleister des Landes Berlin, known as ZIT-BB. Under the programme, all image files uploaded to FIS-Broker and the complementary Stadtentwicklungsportal Berlin are being scanned using perceptual hashing algorithms that flag images sharing more than 95 percent visual similarity. Flagged files are held in a quarantine folder for 30 days before deletion, giving planners at district offices — from Mitte to Lichtenberg — a window to dispute any removal.

How Other Cities Are Tackling the Same Problem

Amsterdam's Gemeente Amsterdam began a comparable review of its Dataportaal in 2024, focusing first on aerial photography from the city's IBA-Expo legacy documentation. According to the municipality's published 2025 annual digital infrastructure report, Amsterdam reduced its geodata image repository by 18 percent in twelve months. Vienna's Stadt Wien took a different approach: rather than automated deletion, the city contracted a manual review cycle through its Wiener Stadtinformation unit, a process critics there have called slower but less prone to accidental loss of historically significant images.

Berlin's automated approach is faster but carries risk. A district planning officer in Friedrichshain-Kreuzberg — one of the highest-volume districts for planning submissions — noted in a February 2026 internal briefing document, published on the Senate's website, that three images flagged for deletion were actually distinct photographs of the same Revaler Straße construction site taken 48 hours apart, relevant to a noise-impact dispute. The algorithmic threshold had treated them as duplicates. The quarantine window caught the error. Paris, which runs a similar deduplication sweep through its Géoportail Paris infrastructure, uses a longer 60-day quarantine period for exactly this reason.

Storage costs are the financial engine driving all of this. Berlin's ZIT-BB pays for cloud archiving on a tiered model; the Senate's digital budget documents from March 2026 reference server storage as one of three line items flagged for cost reduction before the 2027 fiscal year. Cutting duplicate image volume by even 15 percent across the FIS-Broker system is projected to reduce annual archiving expenditure by a meaningful margin, though the Senate has not published a specific euro figure for that projection.

What Comes Next for Berlin's Digital Archives

The programme is scheduled to expand in the fourth quarter of 2026 to cover the Senatsverwaltung für Kultur's own digital image archive, which holds photographs from publicly funded events at venues including the Berliner Festspiele and the Martin-Gropius-Bau. That archive has never undergone systematic deduplication review.

For Berliners who use planning portals to track developments in their neighbourhoods — whether monitoring the ongoing Tempelhofer Feld debate or tracking construction permits along Karl-Marx-Allee — the practical upshot is faster page load times and more reliably current imagery. The ZIT-BB has said the first phase of the programme, covering planning documents, will be complete by September 2026. Whether the lessons from Friedrichshain-Kreuzberg's near-miss prompt a policy tweak — longer quarantine, lower similarity threshold, or mandatory human sign-off for historically significant locations — is still under review inside the Senate Department.