Istanbul Races to Purge Duplicate Images From Its Digital Archives — and Other Cities Are Watching

Istanbul's Metropolitan Municipality has been working through a sprawling problem that most residents never see: thousands of duplicate and near-identical images clogging the digital catalogues used to document the city's public infrastructure, planning records, and cultural heritage sites. The cleanup effort, which accelerated through the first half of 2026, touches databases managed by the İBB (Istanbul Büyükşehir Belediyesi) directorate responsible for urban planning and the separately administered Istanbul Archaeological Museums.

The issue matters now because Istanbul sits at a crossroads of pressures. Post-2023 earthquake retrofitting projects across Fatih and Kadıköy districts require clean, verified photographic records to track structural changes to buildings flagged as seismic risks. Duplicate images — sometimes hundreds of near-identical shots of the same Bosphorus quayside or Sultanahmet facade — slow down automated damage-assessment tools that planners rely on when prioritising demolition or reinforcement orders. Bad data, in a city where the next major tremor is a matter of when not if, is not a bureaucratic nuisance. It is a safety liability.

What Istanbul Is Actually Doing

The İBB's geographic information systems unit, based at the municipality's Saraçhane headquarters in Fatih, began deploying perceptual hash algorithms — software that identifies visually identical or near-identical files — across its urban imagery servers in January 2026. The goal, according to internal project documentation made available through a public procurement notice posted on the Turkish Public Procurement Authority's platform (ekap.kik.gov.tr) in November 2025, was to reduce storage overhead and improve retrieval accuracy for field engineers. The procurement notice listed the contract value at roughly 4.2 million Turkish lira, a figure that reflects the lira's continued weakness against the euro and dollar.

Separately, the Istanbul Archaeological Museums — whose photographic archive of artefacts recovered from digs in Sultanahmet, Yenikapi, and along the Marmaray corridor runs to more than 1.4 million individual image files — launched a parallel deduplication project in March 2026 in partnership with the Ministry of Culture and Tourism. That archive had grown organically since the late 1990s with minimal metadata standards, meaning the same terracotta fragment photographed at slightly different angles across different excavation seasons could exist in dozens of redundant entries.

Neither project is glamorous. Both are essential.

How Istanbul Compares to Rome, Athens, and Cairo

Rome's Sovrintendenza Capitolina began a comparable image-deduplication exercise for its public monument database in 2023, backed by European Union digital heritage funding under the Horizon Europe programme. Athens, managing the Acropolis digital record through the Central Archaeological Council, has faced similar catalogue bloat, though Greek press reports from late 2024 indicate that project remains underfunded. Cairo's Supreme Council of Antiquities has publicly acknowledged that duplicate photographic records across sites in Luxor and Giza complicate international loan requests from major museums — a problem Istanbul's archaeological curators recognise immediately.

What distinguishes Istanbul is scale and urgency combined. The city administers heritage sites under UNESCO consideration, runs one of the busiest port and waterway systems in the world along the Bosphorus, and is simultaneously retrofitting tens of thousands of residential buildings in districts like Bağcılar and Zeytinburnu against earthquake risk. Each of those workstreams generates imagery. Without clean catalogues, the data becomes a liability rather than an asset.

The Saraçhane project is expected to complete its first full audit pass by September 2026, according to the procurement timeline. The archaeological museums' effort has a December 2026 target. Whether the two systems will eventually be interoperable — sharing deduplication standards so a photograph of, say, a Byzantine wall section in Sultanahmet can be consistently identified across both platforms — remains an open question that municipal and ministry officials have not yet publicly resolved.

For residents and urban professionals watching this unfold, the practical takeaway is straightforward: if you submit photographic documentation to İBB for any planning or retrofit application, the municipality's current guidance on its e-municipality portal asks that images be submitted in JPEG format at a minimum resolution of 300 DPI with embedded GPS metadata. Submissions that don't meet those standards are now being flagged automatically rather than manually reviewed, which means delays. Check the portal at ibb.istanbul before filing anything this summer.