Istanbul's Urban Archives Race to Fix a Digital Crisis: Duplicate Images Flooding the City's Planning Databases

Istanbul's metropolitan authority confirmed this week that a system audit across its digital planning infrastructure had flagged more than 40,000 duplicate image files embedded in the city's urban risk and heritage documentation databases — a problem that engineers say has been quietly compounding since a major server migration in early 2025. The discovery, surfaced during a routine compliance review at the Istanbul Metropolitan Municipality's directorate on Saraçhane Square, has forced a temporary halt on several ongoing seismic-vulnerability assessments tied to post-2023 earthquake preparedness efforts.

The timing could hardly be worse. Turkey is three years on from the February 2023 Kahramanmaraş earthquakes, which killed more than 53,000 people across eleven provinces. Since then, Istanbul — which sits atop the North Anatolian Fault and is home to roughly 15 million residents — has been rushing to complete building-by-building risk registers across its 39 districts. Duplicate imagery in those registers is not a bureaucratic nuisance; it means inspectors in the field may be cross-referencing the wrong structure entirely, or confirming a building's safety status against a photograph taken years before any recent retrofitting work.

Where the Problem Sits — and Who Is Fixing It

The affected databases include two critical repositories: the Istanbul Earthquake Risk Reduction and Urban Transformation Project system, coordinated with the Environment, Urbanisation and Climate Change Ministry, and the separate heritage inventory maintained by the Istanbul Archaeological Museums directorate in Sultanahmet. Both systems draw on aerial photography, ground-level survey images and cadastral overlays — and both were migrated to a new cloud infrastructure between March and September 2025. Engineers working on the audit told the municipality's technical board this week that duplication rates in some district-level folders ran as high as 18 percent, meaning roughly one in five images in those folders was a redundant copy pointing to an incorrect metadata tag.

Affected neighbourhoods include Fatih, Zeytinburnu and Avcılar — all three ranked among the city's highest seismic-risk zones by the municipality's own 2022 risk maps. Zeytinburnu in particular has a concentration of pre-1999 residential construction that was built before modern earthquake codes came into force, making accurate photographic records especially critical for prioritising demolition and retrofit orders.

The Istanbul Metropolitan Municipality's digital infrastructure unit has brought in HAVELSAN, the Ankara-based state defence and software company that has worked on government digitisation contracts, to run a deduplication script across the affected servers. A parallel manual verification process, involving 12 field teams, is expected to cover the highest-priority Zeytinburnu and Avcılar files by the end of July 2026.

Heritage Records Also Caught in the Net

Beyond earthquake preparedness, the duplication problem has snarled heritage protection work along the old city walls and in the Süleymaniye district, where conservation teams rely on photographic baselines to detect structural changes season by season. The Istanbul Archaeological Museums flagged to the municipality in June that several Bosphorus-facing façade records — tied to ongoing Bosphorus Development Zone controversies around new construction permits — appeared to reference image files created in 2021 rather than the 2024 surveys that were supposed to replace them. That discrepancy was among the triggers for the broader audit launched this week.

Digital record integrity in municipal planning is not a uniquely Istanbul problem. Warsaw and Lisbon have both reported similar issues following large-scale GIS migrations in recent years. But Istanbul's combination of seismic urgency, a heritage stock spanning Roman, Byzantine and Ottoman periods, and a contested political environment — with Mayor Ekrem İmamoğlu's CHP administration and the AKP-controlled central government frequently at odds over urban transformation powers — adds layers of accountability pressure that other cities don't face in quite the same configuration.

The practical consequence for residents in the affected districts is a delay of four to six weeks in the issuance of new risk certificates, according to the municipality's public timeline posted on its website on July 2. Homeowners in Zeytinburnu who were expecting retrofit subsidy decisions this month under the Urban Transformation Law should check the municipality's e-municipality portal at ebelediye.ibb.gov.tr for updated scheduling. The deduplication process is not expected to require any re-survey of buildings already physically inspected; the problem is confined to the image metadata layer, not the underlying structural assessments themselves.