Istanbul's Duplicate Image Problem: The Key Decisions That Will Shape the City's Digital Archive

Istanbul's municipal digital archive holds an estimated tens of thousands of redundant image files — duplicates accumulated over years of overlapping digitisation drives, departmental data transfers, and poorly coordinated scanning projects across the city's 39 districts. The problem is not abstract. Duplicate records are slowing access to critical planning documents, complicating earthquake-risk assessments, and muddying the heritage inventory for protected sites from Sultanahmet to Balat. The question now is who decides what gets deleted, what gets kept, and who carries the legal responsibility when an image that should have been preserved is gone.

The timing matters. Istanbul sits on the North Anatolian Fault, and urban planners have spent the three years since the February 2023 Kahramanmaraş earthquakes rushing to build out the city's structural vulnerability database. That database relies heavily on photographic records — facade surveys, foundation photographs, before-and-after documentation of reinforcement works. When the same image appears under four different file names across three departments, risk modellers cannot easily confirm whether a building has been photographed once or inspected four times. Getting the archive clean is no longer just an administrative preference; it is a public-safety question.

Where the Decisions Are Being Made

The Istanbul Metropolitan Municipality's Department of Geographic Information Systems, based in the Saraçhane administrative campus near Fatih, has been running a deduplication audit since early 2026. The department is working alongside the Istanbul Earthquake Risk Mitigation and Emergency Preparedness Project — known by its Turkish acronym ISMEP — which has its own image repository covering structural surveys conducted across Avcılar, Bağcılar, and other high-risk western districts. Neither database currently talks to the other in real time, which is precisely the kind of institutional gap that produces duplicate records in the first place.

The Fatih Municipality, responsible for the historic peninsula including UNESCO-listed areas around the Topkapı Palace complex and the Süleymaniye Mosque, runs a separate heritage image bank. Cultural heritage law in Turkey requires that photographic documentation of Category 1 listed structures be retained permanently. That legal obligation means deletion decisions cannot be made on a simple algorithmic basis: a file that looks like a duplicate may carry a unique metadata tag confirming it was taken during a specific licensed restoration survey, making it legally irreplaceable even if the image itself appears identical to three others.

What Happens Next

Three choices are now on the table. The first is a centralised merge: all departmental image libraries fold into a single Istanbul Metropolitan Municipality server, with a unified deduplication protocol applied before the end of 2026. The second option is a federated model, where each department keeps its own archive but adopts a shared metadata standard — a slower process that preserves departmental autonomy but delays the cleanup. The third, and least popular among technical staff, is the status quo: do nothing and accept the growing storage and retrieval costs.

Storage is not cheap. Commercial cloud storage prices for large municipal datasets in Turkey have risen sharply alongside inflation — the Turkish lira lost significant purchasing power through 2024 and 2025 — meaning every redundant gigabyte carries a real budget cost that compounds annually. Municipalities that have already moved toward consolidated archives, including Ankara's metropolitan authority which completed a similar exercise for its urban planning records in 2024, report measurable reductions in retrieval time for planning applications.

For Istanbul, the practical deadline is the renewal cycle for the city's urban transformation contracts, many of which come up for review in the first quarter of 2027. Contractors working on reinforcement projects in Kadıköy and Zeytinburnu are required to submit photographic progress reports into municipal systems. If the archive is still cluttered with duplicates by then, verification of those submissions becomes significantly harder.

Heritage advocates, meanwhile, want written policy guaranteeing that no image linked to a listed structure can be removed by an automated process without human sign-off. That demand is reasonable and the municipality has not yet publicly committed to it. The next scheduled interdepartmental working group on the archive question meets in September 2026 — and the outcome of that meeting will determine whether Istanbul's digital record of its own past is cleaned up deliberately or left to accumulate further disorder.