Istanbul Municipalities Remove Thousands of Duplicate Images From Digital Archives

Istanbul's municipal digital infrastructure took a concrete step forward this week when the Istanbul Metropolitan Municipality's Directorate of Geographic Information Systems announced it had identified more than 14,000 duplicate image files embedded across its urban-planning and Bosphorus development databases — records that had quietly accumulated since a mass-scanning project began in early 2024. The directorate, based at the Saraçhane administrative complex in Fatih, confirmed the cleanup operation launched on Monday, July 1.

The timing matters. Istanbul has been in the middle of an aggressive push to digitise everything from earthquake-risk assessment maps — accelerated after the February 2023 Kahramanmaraş disaster — to the heritage documentation records held for neighbourhoods like Balat and Süleymaniye. When databases carry duplicate images, automated detection tools misread building conditions, flag phantom discrepancies, and slow down the very emergency-readiness workflows the city has been trying to sharpen. A single duplicated aerial photograph of a residential block in Zeytinburnu, for example, can cause a structural-risk algorithm to generate two conflicting vulnerability scores for the same address.

What Triggered the Review

The immediate trigger was a routine audit conducted in late June by the Istanbul Planning Agency — the İBB'ye bağlı İstanbul Planlama Ajansı, headquartered on Büyükdere Caddesi in Şişli — which cross-referenced image metadata from three separate digitisation contracts awarded between 2022 and 2025. Auditors found that a migration error during a server consolidation in March 2026 had caused entire image folders to be ingested twice, sometimes three times, into the central repository. The affected files included drone survey photographs of the Haliç waterfront, scanned cadastral maps from the historic Kapalıçarşı district, and thermal imaging data collected during the municipality's post-earthquake resilience surveys in Avcılar.

Duplicate image problems are not merely a storage inconvenience. Turkey's national Geographic Information Systems standards, updated by the General Directorate of Geographic Information under a 2021 regulation, require that municipal spatial databases maintain unique-image integrity before submitting data to Ankara. Municipalities that fail compliance checks risk losing access to central government co-financing windows — a significant pressure point given Istanbul's current capital budget, which the municipality has publicly described as stretched by lira depreciation and inflation running above 40 percent year-on-year through mid-2026.

The Cleanup in Practice

The actual replacement process involves two phases. First, automated deduplication software — licensed from a Teknopark Istanbul-based firm operating out of the Ataşehir technology zone on the Asian side — scans every image file's hash signature and flags exact or near-identical copies. Second, human reviewers at the GIS directorate manually confirm which version of a disputed image carries the higher resolution or more recent timestamp, then formally retire the redundant files and update all linked database records to point to the canonical copy.

Staff working through the backlog at the Saraçhane offices said this week that roughly 6,200 of the 14,000-plus flagged files had been resolved by Thursday, July 3. The directorate is targeting full completion before July 18, which aligns with an internal deadline tied to a Bosphorus corridor development review scheduled for later that month. Images of the European shoreline between Ortaköy and Bebek are among the records requiring the most manual attention, as multiple aerial survey contractors photographed the same stretches in overlapping flight paths during 2024.

For Istanbul residents and businesses interacting with the municipality's online permit and urban-transformation portals — tools that pull directly from the same image repositories — the practical advice is straightforward. Anyone who submitted a building application or heritage-site inquiry between March and June 2026 and received an automated status update should log back into the İBB e-belediye portal and verify that the property images attached to their file are current. The directorate has posted a reference number — GBS-2026-07-001 — that applicants can cite when contacting the Fatih district office if discrepancies appear. The image audit, unglamorous as it sounds, sits at the foundation of how the city tracks its own built environment.