Barcelona's Digital Archive Problem: The Hidden Scale of Duplicate Images Clogging City Records

Barcelona's city administration is sitting on a digital storage problem that officials rarely discuss publicly but that costs real money every year. Across the Ajuntament de Barcelona's network of databases — covering everything from the Cadastre records in the Eixample district to the public housing inventory managed by l'Institut Municipal de l'Habitatge i Rehabilitació (IMHAB) — duplicate images account for a substantial and growing share of total data storage. Industry benchmarks from European municipal IT audits consistently place duplicate file rates in urban government archives at between 20 and 40 percent of total stored assets.

The timing matters because Barcelona is in the middle of two overlapping crises that generate enormous volumes of photographic data. Mayor Jaume Collboni's crackdown on short-term tourist rentals — which drove the number of licensed Airbnb-style flats down from roughly 10,101 to zero new licences issued after the November 2028 expiry date announced in 2023 — has forced the city's housing registry to rapidly catalogue thousands of properties for compliance checks. At the same time, the port authority's ongoing documentation of cruise ship traffic through the Moll de la Costa terminal generates inspection images that flow into at least three separate departmental systems, none of which are currently synchronised.

Where the Numbers Stack Up

The IMHAB alone manages inspection photography for more than 9,000 publicly subsidised rental units spread across neighbourhoods including Nou Barris, Sant Andreu and the waterfront blocks of La Barceloneta. Each property inspection generates between 15 and 40 digital images. When the same flat is reinspected — standard practice after any complaint or renovation — the new image batch is typically uploaded alongside, not in replacement of, the old one. Without automated deduplication, a single Nou Barris flat can accumulate 200-plus photographs over a five-year tenancy cycle, the majority of which are functionally identical to earlier shots.

Cloud storage is not free. European public-sector cloud contracts — Barcelona's primary infrastructure provider is within the framework of the Generalitat de Catalunya's shared digital services agreement — typically price storage at between €0.018 and €0.023 per gigabyte per month at scale. A municipal archive carrying 30 percent redundant image data on a 500-terabyte image repository wastes the equivalent of 150 terabytes. At mid-range contract rates, that translates to roughly €2,700 per month in avoidable expenditure — more than €32,000 annually before factoring in backup, retrieval and administrative overhead.

The tourism licensing directorate faces a parallel version of the same issue. Since Collboni's administration launched its Pla d'Allotjaments Turístics review process, applicants for any remaining special-category licences must submit exterior and interior photographs through the city's OAC (Oficina d'Atenció Ciutadana) digital portal. The portal lacks a duplicate-detection layer, meaning the same building façade on Carrer de Pelai or a standard kitchen in Gràcia gets uploaded repeatedly by different applicants or re-uploaded after administrative rejections.

What Deduplication Actually Requires

The technical fix is well understood. Perceptual hashing — a process that generates a compact fingerprint for each image and flags near-identical matches regardless of minor resizing or compression differences — can reduce duplicate load by 60 to 80 percent in typical municipal datasets, according to published benchmarks from the EU-funded DECODE project, which Barcelona participated in during its 2017-2019 phase. The city's own Superilla digital infrastructure program, managed through Barcelona Digital City (BDC), has the technical capacity to implement hashing at the point of upload.

What has been missing is a cross-departmental mandate. The Ajuntament's data governance framework, last updated in 2022 under the Digital Rights Plan, does not currently require deduplication as a standard before archiving. Until that changes, individual departments will continue uploading redundant files independently, each one billing against its own IT budget line without visibility into the aggregate waste.

The practical path forward involves three steps: a unified image intake policy across IMHAB, the tourism licensing portal and the port documentation unit; a retroactive deduplication pass on existing archives using open-source tools already licensed by the Generalitat; and a quarterly audit tied to the city's existing smart-city dashboard, which is publicly accessible at the Plaça de Sant Jaume headquarters. None of these steps require new legislation — only a directive from the city's Chief Digital Officer office to make them standard procedure before the next municipal budget cycle closes in October 2026.