São Paulo Tackles the Duplicate Image Problem Strangling Its Digital Public Records — And How It Compares to the World

São Paulo's municipal government is sitting on millions of duplicated digital images inside its public records infrastructure — redundant scans of planning permits, property deeds and urban zoning maps that have been uploaded multiple times across incompatible systems, quietly inflating storage costs and slowing the bureaucratic machinery that residents depend on. The Secretaria Municipal de Gestão, which oversees the city's administrative technology, confirmed the problem exists across multiple departments, though the full scope of the backlog remains under internal review.

The issue has sharpened because of timing. Mayor Ricardo Nunes signed a digital governance modernisation decree in early 2025, committing the city to a unified document management platform by the end of 2026. That deadline is now six months away, and duplicated image files are one of the core technical obstacles standing between the current patchwork of systems and a consolidated digital archive. The pressure is not purely administrative: São Paulo processes more municipal permits than any other city in Latin America, and redundant files slow down approvals for construction, environmental licences and social housing registrations in neighbourhoods already strained by the city's chronic flooding and drainage backlog.

The practical consequences land hardest in offices like the Cartório do 15º Registro de Imóveis in the Centro district and in the Prefeitura's SP156 service portal, where property documentation queries routinely surface duplicate image records that staff must manually reconcile. The Instituto de Tecnologia e Sociedade, based in the Itaim Bibi neighbourhood, has been documenting the problem as part of a broader open-data audit it began in March 2026, flagging that duplicate imagery in georeferenced land-use databases creates compounding errors when layered with flood-risk mapping in low-income zones along the Tietê and Pinheiros river banks.

What Other Cities Are Doing

Seoul tackled a comparable problem between 2021 and 2023 when its Smart City Data Hub — a centralised platform managing urban imagery from more than 4,000 connected cameras and satellite feeds — deployed perceptual hashing algorithms to automatically flag and quarantine duplicate or near-duplicate image assets before they entered the permanent archive. The South Korean capital reduced its redundant image storage by roughly 34 percent within 18 months of deployment, according to a 2023 report published by the Seoul Digital Foundation. Lisbon used a different approach: the city's Arquivo Municipal digitalisation project, running since 2019, built a manual-plus-automated hybrid review layer specifically to handle duplicated scans from the city's 20th-century planning documents, with human archivists making final deletion calls rather than automated systems acting alone.

Nairobi offers a cautionary counterpoint. The Kenyan capital launched a land registry digitisation programme in 2022 with World Bank backing, but duplicate scans from a poorly coordinated multi-vendor rollout created legal complications when two different digital versions of the same title deed appeared in court proceedings in 2024. The case prompted Kenya's Ministry of Lands to pause automated deletion protocols and impose a manual verification requirement, adding months to the timeline and costs that were not originally budgeted.

São Paulo's current approach leans closer to the Lisbon model than Seoul's, at least for now. The Secretaria Municipal de Gestão has issued internal guidance requiring human sign-off before any image file is flagged for permanent deletion from the municipal archive — a conservative posture that archivists and urban planners interviewed for background said reflects the city's cautious reading of the Nairobi experience. The SP-Digital programme, which the Nunes administration funds to the tune of R$180 million annually according to the 2026 municipal budget published in December 2025, is the formal vehicle for the consolidation work.

What Comes Next

The city has set an internal milestone of October 2026 to complete a full audit of duplicated image assets across four priority databases: the urban planning register, the environmental licensing system, the SP156 housing portal and the georeferenced flood-risk platform managed in partnership with the Centro Nacional de Monitoramento e Alertas de Desastres Naturais. Whether that audit produces an automated fix, a Lisbon-style hybrid system or a phased manual review will depend on what the audit reveals about error rates and legal exposure. Residents and businesses waiting on permits tied to those systems have been advised by the Prefeitura to check the SP156 portal directly for status updates and to flag any document inconsistencies through the platform's formal dispute channel, rather than assuming errors reflect deliberate decisions.