How Istanbul's Building Registry Ended Up Drowning in Duplicate Images — and Why Fixing It Took a Decade

Istanbul's İBB Property Directorate confirmed this week that more than 340,000 image files in its central cadastral database had been flagged as duplicates since a cleanup audit began in March 2026 — the clearest measure yet of how badly the city's rushed 2008–2014 digitisation drive distorted official property records across all 39 districts.

The timing matters. Istanbul is in the middle of a court-ordered re-evaluation of building safety certificates under the Kentsel Dönüşüm (Urban Transformation) programme, which accelerated sharply after the February 2023 Kahramanmaraş earthquakes killed more than 53,000 people across southern Turkey. Accurate photographic documentation of a structure — its facade condition, floor count, visible cracks — is now legally required before a demolition-and-rebuild licence is granted. Duplicate or misfiled images can stall that process for months, leaving families in limbo and contractors idle.

How the Backlog Built Up

The problem has deep roots. Between 2008 and 2012, the Tapu ve Kadastro Genel Müdürlüğü — Turkey's national land registry authority — contracted several private data-entry firms to scan paper records from municipal sub-offices scattered across the city, from the cramped Fatih registry office near the Covered Bazaar to the larger facility in Ümraniye on the Asian side. Field teams photographed thousands of buildings using early-generation digital cameras, then uploaded batches via USB drives to a central server. The system had no automated duplicate-detection layer and no mandatory file-naming convention. The same apartment block in Kadıköy could end up with three separate entries under slightly different address strings, each carrying its own set of photographs — or, worse, carrying another building's photographs entirely.

A 2019 internal audit by the Directorate General of Geographic Information Systems, whose Istanbul office sits on Büyükdere Caddesi in Maslak, identified roughly 180,000 suspect files but lacked the budget to resolve them. The work stalled. Then the 2023 earthquakes rewrote the political calculus. The İBB, led by CHP Mayor Ekrem İmamoğlu, pushed hard for a dedicated remediation unit, while the AKP-controlled central government pointed to the national Tapu Kadastro system as the responsible body. Eighteen months of jurisdictional argument followed before a joint working protocol was signed in January 2026, allocating 47 million lira — worth roughly $1.3 million at current exchange rates — to the cleanup effort.

What the Audit Found on the Ground

By April 2026, the joint team had worked through records for Beşiktaş, Şişli and Beyoğlu. The error rate in those three districts averaged 12 percent of all image files — higher than the national estimate of 7 percent that the ministry had cited publicly. In Beyoğlu alone, which includes the dense historic fabric around İstiklal Caddesi and the steep backstreets of Tarlabaşı, auditors found 28,000 files where the geotag coordinates placed the image in a completely different neighbourhood than the address field suggested. Some files from Tarlabaşı buildings had been indexed under parcels in Sarıyer, more than 15 kilometres to the north.

The lira's chronic weakness adds a practical edge to the bureaucratic mess. Construction costs in Istanbul have risen more than 400 percent in nominal terms since 2021. Every week a building permit is delayed because its registry record needs photographic correction costs a developer real money at today's prices — and often costs residents extended stays in temporary accommodation that the government's AFAD disaster agency is no longer fully subsidising.

The joint directorate says it expects to complete the 39-district audit by the end of November 2026, prioritising high-seismic-risk zones identified under the updated İstanbul Deprem Master Planı. Property owners who suspect their building's file may be affected can check reference numbers through the e-Devlet portal and file a correction request at their local Tapu müdürlüğü — the Kadıköy branch on Söğütlüçeşme Caddesi being one of the busier walk-in offices. Officials are recommending that anyone with an active urban transformation application bring physical copies of original title deeds and any contractor survey photographs dated before 2015, precisely because the digital record may not be reliable.