Istanbul's Digital Archive Push Puts Duplicate Image Problem in the Spotlight This Week

Istanbul's Fatih Municipality confirmed this week that an internal audit of its digital property records had uncovered thousands of duplicate images clogging its cadastral database — some files triplicated or worse — slowing the system used by officials processing building permits and earthquake-risk assessments across one of the city's most densely built districts. The discovery has prompted an emergency review of data protocols at several other municipal directorates.

The timing is not accidental. Turkey's central government set a July 1, 2026 deadline for all municipalities to align their digital records with the national e-Devlet infrastructure upgrade, a programme that links local land registries, utilities, and urban planning files into a single federal platform. For Istanbul, a city of roughly 16 million people sitting on top of two active fault lines, accurate visual documentation of building stock is more than an administrative inconvenience — it is a seismic-safety issue that has been under intense scrutiny since the February 2023 Kahramanmaraş earthquakes.

Where the Problem Showed Up First

Two institutions became focal points this week. The first is the Istanbul Metropolitan Municipality's Urban Transformation Directorate, headquartered on Kasımpaşa Caddesi in Beyoğlu, which manages the city's high-risk building inventory. Staff there discovered that drone-survey imagery collected between 2021 and 2024 had been stored in at least three separate folder hierarchies, with no deduplication process in place. Hundreds of neighbourhood blocks in Zeytinburnu — one of the districts flagged as highest-risk by the İstanbul Deprem Risk Haritası — appeared in the database multiple times under different file-naming conventions.

The second institution is the Istanbul Archaeological Museums complex near Sultanahmet, where conservators have been digitising fragile photographic collections since 2019 under a project co-funded with the European Union's IPA II instrument. Archivists this week told the museum's digital committee that roughly 14,000 image files in the collection had been ingested twice, in some cases with conflicting metadata, making it impossible to confirm provenance without manual cross-checking. The museums house more than one million objects; the digital catalogue is supposed to be their public-access front door.

Duplicate image accumulation is a known problem in large-scale digitisation work, but Istanbul's situation has a specific local driver: staff turnover. Municipal technology departments have seen high churn as lira-denominated salaries have failed to keep pace with inflation, which the Turkish Statistical Institute put at 44.38 percent year-on-year as of May 2026. Experienced data managers who understood legacy file structures left, and their replacements often rebuilt workflows from scratch rather than inheriting them, duplicating content in the process.

What Cleanup Looks Like in Practice

The Urban Transformation Directorate has contracted with Ankara-based software firm NetKadastro to run a hash-matching deduplication sweep across approximately 2.3 terabytes of imagery before the end of August. The process compares cryptographic fingerprints of image files to identify exact duplicates without human review of each photo — a method that works well for identical files but struggles with near-duplicates taken from slightly different angles or under different lighting, which is a genuine complication for street-level building surveys.

For the Archaeological Museums, the fix is slower. Conservators plan a phased metadata reconciliation through a working group that includes staff from Boğaziçi University's digital humanities programme. Phase one, covering images from the Tiled Kiosk collection, is scheduled to conclude by September 30. The broader collection will take longer.

Anyone with a professional stake in Istanbul's digital records — architects, contractors, heritage researchers, or residents waiting on urban transformation paperwork in Zeytinburnu, Bağcılar, or Avcılar — should expect some processing delays through late summer as systems are reviewed. The Fatih Municipality has set up a dedicated inquiry line through its e-Belediye portal for permit applications stalled by the audit. Getting familiar with that channel now is the practical move, rather than queuing at the district office on Macar Kardeşler Caddesi where walk-in processing has slowed considerably this week.