Istanbul's Battle Against Duplicate Images in Urban Records: How It Stacks Up Against Rome, Barcelona and Seoul

Istanbul's metropolitan municipality confirmed earlier this year that its digitised urban archive holds an estimated 4.2 million photographs catalogued since a major digitisation push began in 2019 — and auditors flagged that roughly 18 percent of those images appear as duplicates, straining storage servers and slowing down heritage permit applications across the city. The figure emerged from an internal review by the Istanbul Metropolitan Municipality's Geographic Information Systems directorate, which manages spatial and documentary records for all 39 districts.

The timing matters. Turkey's broader push to digitalise municipal services accelerated after the February 2023 Kahramanmaraş earthquakes exposed dangerous gaps in building inspection records, including cases where the same structural survey photographs had been filed under multiple addresses. In Istanbul, where seismic risk sits at the top of every planning agenda, a duplicate image in a building assessment file is not a bureaucratic nuisance — it can mean a dangerous structure gets cleared twice or a legitimate record gets buried.

What Istanbul Is Actually Doing About It

The municipality's answer has been the AKOS platform — short for Açık Kent Veri Sistemi, or Open City Data System — which went live for internal users in March 2025 and began a phased public rollout in the Beyoğlu and Fatih districts in October of that year. AKOS uses perceptual hashing algorithms to flag near-identical images before they enter the archive, rather than cleaning up after the fact. The Fatih district alone, home to the UNESCO-listed Historic Peninsula including the Sultanahmet mosque complex and the Covered Bazaar, generates hundreds of new permit-related photographs every week.

A second initiative runs through TÜRKSAT, the state satellite and technology company, which has been contracted to assist with deduplication across registries that include Syrian refugee documentation held at the Istanbul Provincial Directorate of Migration Management on Vatan Caddesi in Fatih. That registry, covering more than 500,000 registered Syrians in the city as of 2024 figures published by the Interior Ministry, had accumulated duplicate biometric images partly because families registered at multiple service points during peak migration years between 2015 and 2019.

How Istanbul Compares to Rome, Barcelona and Seoul

Rome's municipal archive authority, the Archivio Storico Capitolino, completed a deduplication project for its photographic collection in 2023 after a three-year European Union co-funded programme. Officials there reported reducing duplicate entries by 23 percent across 1.1 million digitised items. Barcelona's Institut Municipal d'Informàtica adopted automated deduplication as standard procedure for all new uploads in 2021, meaning the city largely avoided a backlog problem rather than having to solve one retroactively.

Seoul presents perhaps the most instructive parallel. South Korea's capital ran a citywide Smart Archive Consolidation Project between 2020 and 2023, spending approximately 14 billion Korean won — roughly 10 million US dollars at 2023 exchange rates — to unify 11 separate municipal image databases. Seoul's approach prioritised interoperability across departments before tackling duplication, a sequence Istanbul has essentially reversed by attacking duplicates first and planning full integration later. Urban data specialists at Seoul's city research institute published a case study in February 2024 noting that tackling duplicates without first resolving metadata standards created secondary inconsistencies that required a second round of corrections.

Istanbul's AKOS project budget has not been made public in full, though the municipality's 2025 capital expenditure summary, approved by the city council in December 2024, allocated 280 million Turkish lira to digital infrastructure broadly — a category that includes but is not limited to the archive deduplication work. At current exchange rates, that sum represents considerably less than Seoul's dedicated spend, a gap that reflects both the lira's long depreciation and competing fiscal priorities across a city of 15 million people.

For residents, the most immediate practical effect will be felt in planning and heritage applications. The Tarihi Yarımada Koruma Kurulu — the Historic Peninsula Protection Board — processes hundreds of renovation permits annually for properties in Sultanahmet, Eminönü and Zeyrek. Officials have said the AKOS rollout should cut duplicate-related processing delays for those applications by the end of 2026. Anyone with a pending permit tied to an address in Beyoğlu or Fatih can check the status through the municipality's e-belediye portal, where a new image-verification flag was added in May. For other districts, the phased expansion is scheduled to reach Kadıköy and Üsküdar on the Asian side before the end of the year.