Istanbul's Digital Archive Push Hits Snag Over Thousands of Duplicate Images in Heritage Database

Thousands of duplicate and mislabelled photographs have been identified inside Istanbul's municipal cultural heritage database, causing delays for urban planners and earthquake-resilience teams who rely on accurate building records across the city's oldest districts. The problem surfaced publicly this week after the Istanbul Metropolitan Municipality's directorate for urban transformation flagged the backlog in internal documents reviewed by The Daily Istanbul.

The timing is not accidental. Turkey's government accelerated digital inventory requirements for all municipalities following the February 2023 Kahramanmaraş earthquakes, mandating that cities maintain verified, non-duplicate photographic records of buildings in high-risk zones. Istanbul, which sits on the North Anatolian Fault and houses an estimated 90,000 structures deemed vulnerable to seismic damage according to municipal risk assessments, has been under pressure to get its records clean before the next round of national compliance checks, scheduled for September 2026.

Where the Problem Is Concentrated

The duplication issue is worst in Fatih and Beyoğlu, two districts where rapid urban transformation projects overlap with dense Ottoman-era building stock. Teams working under the Istanbul Metropolitan Municipality's KUDEB unit — the body responsible for protecting historically registered structures — have reportedly been cross-referencing records from at least three separate digitization drives conducted between 2019 and 2024. Those drives used different file-naming conventions and metadata standards, producing cases where the same building facade appears dozens of times under different registry codes.

The Süleymaniye neighbourhood in Fatih is one flashpoint. Surveyors there have been working since Monday to reconcile image records for more than 200 registered structures along Mimar Sinan Caddesi and the surrounding streets, according to a schedule posted on the municipality's open-data portal. Similar reconciliation work is underway in Karaköy, where heritage buildings near the Galata Tower have been photographed repeatedly by different contractors since the waterfront redevelopment discussions began in 2022.

The Istanbul Foundation for Culture and Arts, known as İKSV, which maintains a separate but partially linked archive of heritage venue imagery for its event and tourism programming, confirmed this week that it had also begun an internal audit after receiving mismatched files from a municipal data-sharing agreement signed in March 2026.

What the Duplication Actually Costs

Duplicate imagery is more than a filing nuisance. Each unresolved duplicate can stall a building permit review, since inspectors must confirm they are examining the correct structure before approving or rejecting earthquake-retrofit applications. The municipality's urban transformation office has said publicly that permit processing in high-risk zones currently takes an average of 47 working days — well above the 20-day target set under the national Urban Transformation Law.

Storage costs add up too. Municipal cloud infrastructure contracts, tendered publicly through the Electronic Public Procurement Platform in 2024, show the city paying for image repository capacity that technical staff say is inflated by redundant files. The deduplication work being done this week uses software licensed through a framework agreement the municipality holds with a domestic technology supplier — the contract, worth roughly 8.4 million lira annually, covers automated hash-matching tools that flag identical or near-identical image files for human review.

Heritage preservation advocates have long argued that Istanbul's fragmented approach to digitization — with separate systems run by the municipality, the national Directorate General of Foundations, and private restoration contractors — was always going to produce exactly this kind of overlap. The current cleanup effort is the most systematic attempt yet to address it, but reviewers say the September compliance deadline is tight.

For residents in Fatih and Beyoğlu waiting on retrofit permits, the practical advice from the municipality's urban transformation hotline — 444 89 42 — is to re-submit any application flagged as pending for more than 30 working days, attaching fresh photographs with GPS metadata enabled. That step, officials have noted in public guidance documents, helps reviewers bypass the disputed legacy records entirely and process files from clean data. The deduplication drive is expected to conclude by late August, though the volume of flagged images — unofficially estimated in the tens of thousands — suggests that deadline may slip.