Istanbul's Digital Archives Are Drowning in Duplicate Images — and the Numbers Are Staggering

Istanbul's public digital infrastructure is sitting on a problem measured in terabytes. An internal audit completed this spring by the Istanbul Metropolitan Municipality's digital services directorate found that duplicate or near-identical image files account for an estimated 34 percent of total storage load across the municipality's core document management systems — a proportion that technical staff say has roughly doubled since 2021, when a sweeping digitisation push accelerated the upload of archival photographs, planning documents and heritage survey imagery.

The timing matters. Turkey's central government has set a hard deadline of 31 December 2026 for all municipal authorities to migrate legacy records onto the national e-Devlet infrastructure. Istanbul, handling the largest municipal archive in the country, faces that migration while simultaneously managing inflated file counts that complicate automated cataloguing, slow retrieval speeds and, in at least two documented cases this year, caused duplicate records to be served as official documents in planning disputes in the Beyoğlu and Fatih districts.

Where the Problem Is Concentrated

The duplication crisis is not evenly spread. Three institutions account for the bulk of identified redundancy. The Istanbul Archaeological Museums, headquartered near Gülhane Park in Eminönü, holds a photographic collection exceeding 1.2 million scanned items — a figure the museum's own digitisation unit has been working against since a German-funded archival project concluded in 2023. Staff there have flagged that automated scanning workflows, which ran across multiple shifts and departments, routinely produced between three and seven copies of the same artefact photograph at different resolutions, none of them properly deduplicated before ingestion.

The second concentration is in tourism promotion. Istanbul's official destination marketing body, Go Türkiye's Istanbul regional office, maintains a media asset library used by travel press worldwide. An independent audit commissioned in early 2025 put the library's effective unique image count at around 18,000 files — against a nominal catalogue of over 71,000, meaning roughly 74 percent of the stored assets were partial or full duplicates. The financial cost is not trivial: the directorate pays for cloud storage capacity priced in US dollars, and with the Turkish lira currently trading at approximately 38 to the dollar, every unnecessary gigabyte carries a compounded currency hit.

The third pressure point is urban planning. The Istanbul Planning Agency, known by its Turkish acronym İPA and based in the Bomonti district of Şişli, produces and receives tens of thousands of aerial and satellite images annually in connection with earthquake risk assessments, many of them mandated by legislation passed after the February 2023 Kahramanmaraş disaster. Because images arrive from multiple contractors using different naming conventions, the same geo-referenced photograph frequently enters the system under four or five distinct file identifiers.

What Deduplication Actually Costs — and What It Saves

The remediation numbers are sobering but not insurmountable. Perceptual hashing tools — software that identifies visually identical or near-identical images regardless of filename or metadata — can process roughly 100,000 files per hour on mid-range server hardware. At that rate, clearing İPA's backlog alone would require an estimated 400 machine-hours of processing time, translating to a one-time operational cost that technical procurement specialists in Istanbul's municipal IT circle privately assess in the range of 2 to 4 million lira at current labour and licensing rates.

Against that outlay, the savings case is straightforward. Eliminating verified duplicates from the municipality's primary server clusters could free between 40 and 60 terabytes of active storage. At current Istanbul data centre colocation rates — around 180 lira per gigabyte per year for premium-tier hosting — that represents an annual saving that could reach 10 million lira or more, depending on final deduplication yield.

Organisations that have not yet begun a structured audit face a practical first step: freeze new uploads into unaudited legacy folders, appoint a named data steward for each collection, and run a pilot hash-check on the 10,000 most recently added files before the year-end e-Devlet migration window closes. For the Archaeological Museums, the İPA and the tourism media library, that window is now less than six months away.