How the Central Coast Is Tackling Duplicate Image Replacement in Public Records — and How It Stacks Up Against Cities Worldwide

Central Coast Council is midway through a technical audit of its digital asset registers, targeting thousands of duplicated images embedded in planning applications, flood mapping layers and infrastructure records that accumulated during the governance crisis that placed the council under state administration between 2020 and 2021. The cleanup is part of a broader data integrity program tied to the council's ongoing IT systems overhaul, which is running alongside the Gosford CBD renewal precinct work centred on Mann Street and the redevelopment corridor stretching toward the Gosford waterfront.

The timing matters. Councils across New South Wales are under increasing pressure from the NSW Department of Planning to submit clean, audit-ready digital records as the state pushes housing approvals through faster consent pathways. Bloated or duplicated image files slow those systems, cause version-control failures in development applications, and — in flood-prone areas like Tuggerah and Toukley — can result in planners referencing outdated inundation mapping. With Sydney recording its hottest June since 1859, climate resilience documents that include aerial photography, drainage overlays and hazard imagery are being updated at a faster rate than ever before, making the duplicate problem more acute by the month.

A Local Problem With a Surprisingly Global Comparison

The Central Coast is not alone. Rotterdam's municipal authority, which manages one of Europe's most digitised port and urban planning systems, completed a similar de-duplication exercise across its geospatial records database in 2023, reducing file storage by roughly 34 percent across its GIS holdings, according to a published case study from the Dutch Urban Data Centre. Medellín's Planning Secretariat undertook comparable work in 2022 as part of its open-data reforms, after auditors found that duplicated parcel imagery was causing discrepancies in building permit approvals across the city's hillside comunas. Both cities used automated hash-matching tools to flag duplicate files before human review.

Central Coast Council's approach, based on publicly available tender documents released through the NSW eTendering portal in early 2026, involves a contracted GIS services provider working with the council's in-house spatial data team based at the Wyong administration centre on Hely Street. The work covers records held within the council's property information system, as well as layers within its publicly accessible mapping portal, which residents in areas including Woy Woy, The Entrance and Gosford regularly use to check flood risk and development overlays on their properties.

What the Numbers Suggest

Industry benchmarks published by Esri, the GIS software company whose platforms are used by a large share of Australian local governments, suggest that unmanaged document repositories at councils of comparable size to Central Coast — which serves a population of around 340,000 people across more than 1,800 square kilometres — can accumulate duplicate imagery rates of between 15 and 25 percent of total stored files within five years of a major system migration. Central Coast underwent exactly such a migration during the administration period. The council has not publicly released its own duplication rate figures to date.

The cost implications are real. Cloud storage contracts for local government spatial data in NSW are typically priced on volume. Removing redundant files from a repository of the scale managed from Hely Street can reduce ongoing licensing and storage costs, while also cutting the time development assessment officers spend cross-checking which version of a site photo or aerial image is current. For homeowners in places like Wamberal — where coastal erosion and flooding intersect in ways that directly affect insurance and property values — having clean, current imagery in the council's records is not a bureaucratic detail. It affects valuations, planning certificates and loan approvals.

The council's spatial data team is expected to complete the initial audit phase by the end of the third quarter of 2026, with any public-facing map portal updates to follow in the final quarter. Residents who want to flag suspected mapping anomalies on their properties — outdated aerial photos, mismatched flood overlays, or duplicate entries in the development register — can submit a request through the council's online service portal or attend one of the drop-in planning information sessions held fortnightly at the Gosford Library on Baker Street.