Barcelona's Duplicate Image Problem: The Key Decisions That Will Shape the City's Visual Archive

Barcelona's drive to digitise its public record has hit a familiar snag. Across several municipal platforms — from the Institut Municipal d'Informàtica's urban planning portal to the Arxiu Municipal Contemporani de Barcelona on Carrer de Sant Pau — thousands of duplicate image files have accumulated over years of parallel scanning projects, rushed data migrations and overlapping departmental uploads. Now, with a city-wide audit of digital infrastructure either underway or imminent, the question of what happens to those redundant files has moved from IT housekeeping to a genuine policy decision.

The timing matters. Mayor Jaume Collboni's administration has staked part of its modernisation agenda on open-data transparency, particularly as scrutiny of tourism management and short-term rental enforcement has intensified public demand for accessible, reliable civic records. A cluttered, inconsistent image archive undermines that ambition directly. Decisions made in the coming months will determine not just storage costs, but which version of a document, a street, or a planning application becomes the definitive public record.

Where the Problem Is Most Acute

The duplication issue surfaces most visibly in two areas. First, the city's urban planning files — held across both the Ajuntament de Barcelona's Seu Electrònica and internal systems at the Institut Municipal d'Informàtica on Carrer 60, Zona Franca — contain multiple scanned versions of the same permit drawings, some at different resolutions, some with conflicting metadata timestamps. Second, the photographic collections tied to neighbourhood renewal projects in Poblenou and the 22@ innovation district have been uploaded by different departments without a unified naming protocol, producing near-identical images catalogued under different reference codes.

This is not a trivial administrative inconvenience. When a journalist, a researcher, or a citizen submits an information request under Spain's Ley 19/2013 de transparencia, the responding official must identify the authoritative file. If two images of the same planning document exist with different scan dates, the choice of which one to release can, in theory, affect the outcome of a legal or administrative dispute.

The 22@ district alone — a 200-hectare technology and innovation zone covering much of the former industrial Poblenou — has been the subject of continuous planning revisions since the original 2000 urban plan. Each revision cycle has generated new batches of digitised materials, and cross-referencing them with earlier versions has reportedly stretched the capacity of the Arxiu Municipal's existing deduplication workflow.

The Decisions Ahead

Three choices now sit on the table for city administrators. The first is automated deduplication: deploying software that flags pixel-level or hash-matched duplicates for deletion or archiving. Several European municipal archives — including those in Amsterdam and Vienna — have adopted this approach over the past five years, though neither city's implementation has been without controversy over what gets permanently removed versus merely suppressed.

The second option is a manual audit protocol, assigning archivists to review flagged duplicates case by case. This preserves institutional judgment but is slow and expensive. The Arxiu Municipal Contemporani currently holds more than 1.5 million digitised items across its collections; even a partial manual review of duplicate image clusters would require dedicated staffing through at least 2027.

The third path — and the one with the most significant long-term implications — is a unified metadata standard applied prospectively, allowing duplicates already in the system to persist but preventing new ones. This is effectively a bet that the existing duplication problem will become manageable as old files are accessed less frequently and new uploads comply with fresh rules.

The Collboni administration's digital governance team is expected to present a framework to the Consell Municipal before the end of the third quarter of 2026. Whatever approach is chosen, it will affect how the city's open-data portal — accessible at opendata-ajuntament.barcelona.cat — functions for residents, planners and developers. The short-term rental enforcement data that the city has been publishing as part of its crackdown on illegal tourist apartments is among the image-heavy datasets most affected. Getting the archive right, in other words, is no longer just an archivist's concern.