How Istanbul's Digital Archives Ended Up Full of Ghosts: The Story Behind the Duplicate Image Crisis

Istanbul's municipal digital archives contain hundreds of thousands of images that exist more than once. Some files appear three, four, even a dozen times across different servers, catalogued under different names, assigned to different departments, occasionally tagged with contradictory metadata. The Istanbul Metropolitan Municipality — known by its Turkish acronym IBB — has been attempting to consolidate these records since at least 2021, but the problem predates that effort by at least two decades.

The issue matters now because the IBB is mid-way through a broader smart-city infrastructure push that depends on clean, reliable visual data. Traffic management systems along the E-5 highway corridor, heritage documentation for neighbourhoods from Balat to Üsküdar, and the seismic-vulnerability mapping programme that accelerated sharply after the February 2023 Kahramanmaraş earthquakes all draw on centralised image repositories. Duplicate files slow retrieval, inflate storage costs, and — in the case of building-condition surveys — risk feeding outdated photographs into structural assessments.

How the Archive Became a Labyrinth

The roots of the duplication problem run back to the late 1990s, when different Istanbul directorates began digitising their own photograph collections independently. The Directorate of Cultural Heritage and Museums, headquartered near Sultanahmet, maintained one system. The urban planning teams working out of offices in Şişli kept another. The water and sewage utility ISKI had a third. When the IBB attempted its first cross-departmental data migration around 2005, files were copied rather than moved — a shortcut that immediately seeded the duplication.

Two subsequent technology upgrades, one roughly in 2011 and another following the IBB's administrative overhaul after Mayor Ekrem İmamoğlu took office in 2019, each imported legacy datasets without first deduplicating them. By some internal estimates circulated in municipal technology working groups — estimates that have not been formally published — the redundancy rate in certain heritage-photography folders exceeds 40 percent. That figure has not been independently verified, and the IBB has not released an official audit.

The 2023 earthquake response sharpened the stakes considerably. Rapid building-inspection teams fanning out across districts like Zeytinburnu and Avcılar — both flagged as high seismic-risk zones — were photographing structures and uploading images from mobile devices directly into a field-assessment platform that fed back to a central repository. Speed was the priority. Deduplication was not. Engineers later found that multiple inspection visits to the same building sometimes produced separate image sets filed as if they belonged to different structures, complicating the risk-scoring process.

What a Fix Actually Requires

Solving the problem is not simply a matter of running deduplication software overnight. Istanbul's archive spans multiple proprietary systems, some of which use formats that predate current interoperability standards. The IBB's information technology directorate has been working with a consortium that includes Turkish technology firms to build a unified asset-management layer, a project with a planned completion date that has already slipped from an initial 2024 target.

The heritage-preservation dimension adds another layer of complexity. Organisations like ÇEKÜL Vakfı, the Foundation for the Protection and Promotion of the Environment and Cultural Heritage, have long argued that Istanbul's built-environment photograph collections are irreplaceable historical documents. Automated deduplication algorithms that prioritise the most recently uploaded version of a file risk deleting older images that carry documentary value the metadata does not capture.

For now, archive managers are being asked to apply a hybrid approach: automated flagging of probable duplicates followed by human review for any file tagged to a heritage site or a building under active seismic assessment. It is slow, expensive, and dependent on staffing levels that fluctuate with the city's chronic budget pressures — pressures made worse by lira depreciation that has pushed technology procurement costs sharply higher since 2021.

The practical advice for anyone depending on IBB visual data in the near term is straightforward: cross-reference any image retrieved from the central repository against the originating directorate's own records, particularly for properties in Fatih, Beyoğlu, and the Bosphorus shoreline zones where both heritage and seismic documentation overlap. The unified system, when it arrives, should render that workaround unnecessary. Until then, the ghosts remain.