How Istanbul's Building Stock Ended Up Full of the Wrong Records: The Story Behind the Duplicate Image Crisis

Istanbul's land registry has a problem it can no longer paper over. Tens of thousands of property files held by the Tapu ve Kadastro Genel Müdürlüğü — Turkey's General Directorate of Land Registry and Cadastre — contain duplicate or mismatched satellite and survey images, a legacy of at least three separate digitisation drives carried out between 1999 and 2019. The directorate acknowledged the scope of the backlog in internal guidance circulated to provincial offices earlier this year, setting a remediation timeline that runs through the end of 2026.

The timing matters. Istanbul sits on the North Anatolian Fault, and since the catastrophic February 2023 Kahramanmaraş earthquakes killed more than 50,000 people across southern Turkey, municipal authorities and the central government have accelerated urban transformation projects across the city. Accurate, clean property records are not an administrative nicety — they are the legal foundation for demolishing unsafe buildings, compensating displaced owners, and issuing new construction permits. Duplicate images in a cadastral file can stall a transformation project for months, sometimes years.

Three Digitisation Waves, Three Sets of Problems

The roots of the crisis run back to 1999. After the Marmara earthquake killed more than 17,000 people, a rapid field re-survey of Istanbul's most at-risk districts produced a wave of new cadastral maps. Those maps were scanned and entered into an early database system, but the resolution standards of the time were inconsistent. A second digitisation push, funded partly through a World Bank urban development loan and carried out between roughly 2008 and 2012, overlaid new high-resolution aerial photography on the same files without always retiring the older images. A third pass, completed around 2019 under TKGM's e-Devlet integration programme, pulled records into the national online portal and, in doing so, sometimes duplicated image attachments rather than replacing them.

The result is a layered mess. In Kadıköy and Üsküdar on the Asian side — two districts undergoing some of the heaviest urban transformation activity — property officers have described informally to colleagues a situation where a single parcel can carry three separate images dated years apart, with no flag indicating which is authoritative. The Fatih district on the European side, where Ottoman-era plot boundaries were redrawn multiple times during the 20th century, is regarded internally as among the most complex.

TKGM has not published a citywide count of affected files, but the directorate's 2025 annual performance report, publicly available on its website, noted that the e-Kadastro cleanup initiative had processed approximately 1.2 million records nationally in that calendar year, with Istanbul accounting for the largest share of flagged anomalies. The report did not break out image-duplication cases specifically from other data errors.

What the Fix Looks Like on the Ground

The current remediation approach assigns dedicated review teams to each of Istanbul's 39 districts, working from a priority list that puts earthquake-risk zones and active urban transformation corridors first. The Bağcılar and Sultangazi districts in the European northwest — both designated high-seismic-risk areas under the Istanbul Metropolitan Municipality's 2024 earthquake master plan — are understood to be in the first tranche.

For property owners, the practical consequence of the cleanup is mostly invisible unless they are mid-transaction. Notaries at the Beyoğlu and Şişli registry offices have noted that title transfer appointments are running longer than usual this summer as officers manually verify image records before finalising deeds. Standard transfer fees remain unchanged — the base rate is 4 percent of declared property value, split equally between buyer and seller — but delays are adding indirect costs in a market where mortgage rate lock-in windows are short given Turkey's still-elevated interest environment.

The directorate's internal deadline of December 31, 2026 for completing the first-pass image audit is ambitious. District offices have been told to escalate any parcel where automated matching tools cannot resolve the duplication to a senior geodesist for manual review. Whether the staffing exists to clear that queue before the year is out will depend in part on the supplementary budget discussions expected in parliament this autumn. In the meantime, anyone buying or selling property in Istanbul's transformation districts should factor in a buffer of at least two to three extra weeks for registry processing.