Tunis Wrestles With a City Map Cluttered by Duplicate Images — and It Is Not Alone

Tunis city authorities have launched a structured review of duplicate imagery embedded across municipal geographic information systems, targeting thousands of redundant files that have accumulated over more than a decade of uncoordinated urban mapping. The effort, driven by the Agence Foncière Urbaine and supported by technical staff at the Direction Générale des Systèmes d'Information de la Commune de Tunis, marks the most systematic attempt yet to clean up a digital record that officials acknowledge had grown unwieldy.

The problem is not trivial. Municipal GIS databases that carry duplicate images — aerial photographs, street-level captures, satellite tiles stitched from different surveys — slow down query response times, inflate storage costs and, critically, confuse planning decisions when outdated imagery sits alongside current data with no clear hierarchy. For a city like Tunis, where urban development pressure is concentrated in corridors from La Marsa down through the Lac district to Bab Souika, bad data has practical consequences for infrastructure approval timelines.

What Tunis Is Actually Doing

The review covers imagery held across three primary systems: the cadastral archive maintained by the Agence Foncière Urbaine on Avenue Mohamed V, the photographic survey layers held by the Institut National de la Cartographie et de la Télédétection at its facility in the Cité El Khadra neighbourhood, and the operational mapping layer used by the commune's urban planning directorate. Technical staff are cross-referencing file metadata, capture dates and geolocation tags to flag duplicates before any deletion is approved by a committee that meets fortnightly.

A pilot phase run between January and April 2026 identified more than 14,000 duplicate image files across two of the three systems, according to an internal progress note circulated to senior staff and reviewed by this newspaper. The combined redundant storage was estimated at approximately 2.3 terabytes. That figure matters because the commune's current cloud storage contract, due for renegotiation in March 2027, is priced partly on volume. Clearing confirmed duplicates before that renewal could reduce storage costs meaningfully, though the precise saving depends on final audit numbers not yet published.

Comparable programmes elsewhere give a useful yardstick. Casablanca's Agence Urbaine du Grand Casablanca completed a similar deduplication exercise for its metropolitan mapping archive in 2024, reducing redundant imagery by roughly 30 percent over an eight-month cycle. Istanbul's municipality, which manages one of the largest urban GIS repositories in the Mediterranean region, has run automated hash-matching protocols since 2022 to prevent duplicate ingestion at the point of upload — a preventive approach rather than the retrospective cleanup Tunis is now undertaking. Amman launched a comparable audit of its Greater Amman Municipality mapping layers in late 2025, with results expected later this year.

Why the Manual Approach Carries Risk

Tunis is relying predominantly on human review for deletion decisions rather than automated hash-matching, which introduces both a quality guarantee and a pace problem. With two committee meetings per month and hundreds of flagged files requiring sign-off, the full three-system audit is not expected to conclude before the second quarter of 2027. That timeline leaves the March 2027 storage contract renegotiation tight.

Urban technology specialists who study North African municipal infrastructure — without naming individuals here — have pointed to the core difficulty: cities that did not build deduplication protocols into data ingestion workflows in the 2010s are now paying for cleanup retrospectively, often under budget pressure. Tunis is not unusual in this regard. What sets it apart, for now, is the decision to run a transparent multi-agency committee process rather than delegate the task entirely to a private contractor, as several comparable cities have done.

Residents and businesses in districts like Le Bardo and Ariana that interact with the commune's online planning portal may notice intermittent slowdowns during active audit periods — the systems team has flagged scheduled maintenance windows on the commune website. The practical advice for anyone submitting a planning or cadastral query before mid-2027 is to download and save any map outputs at the point of generation, since imagery layers are being updated on a rolling basis and a document generated today may reference different base imagery than one generated in three months' time.