Councils worldwide are purging duplicate property images from planning databases — Central Coast is still catching up

Central Coast Council's digital planning portal still carries hundreds of duplicate cadastral images across its property records system — a data hygiene problem that peer councils in the Netherlands, Canada and parts of the United Kingdom began systematically addressing as far back as 2021. With Gosford's CBD renewal precinct generating a surge of new development applications, the volume of duplicate imagery attached to individual land parcels has grown, slowing assessment workflows in the council's planning and environment directorate on Mann Street.

The timing matters. NSW is midway through its post-Housing Accord push to accelerate approvals, and the state government has been pressing councils to cut median DA determination times. Duplicate image records — where the same site photograph, aerial tile or heritage elevation drawing is stored multiple times under different file identifiers — add friction to that process. Planners cross-checking submissions against council's internal GIS layer must manually reconcile conflicts before a file can progress. It is an unglamorous problem, but a consequential one.

What other cities have already done

The City of Groningen in the Netherlands completed a full deduplication audit of its spatial data holdings in 2022, cutting its land registry image database by roughly 34 percent and reducing average planner query time on complex files by around 12 minutes per case, according to a Kadaster Netherlands technical report published that year. Calgary's municipal planning department in Alberta ran a comparable project across its development permit system in 2023, retiring more than 18,000 redundant image files and integrating a hash-matching tool into its document management platform. Neither project required extraordinary expenditure — Calgary's was completed for approximately CAD $280,000 using existing vendor contracts.

Closer to home, the City of Newcastle in the Hunter region began a phased deduplication program through its Pathway DA management system in late 2024, after an internal audit found that duplicate attachments were contributing to file-size limits being exceeded on large subdivision applications. Newcastle's experience is directly relevant to Gosford because both councils run comparable Pathway configurations administered through Technology One, the Brisbane-based software provider that also supports Central Coast Council's back-end planning systems.

Central Coast Council emerged from state-imposed administration in 2021 after a financial crisis that forced significant cuts to technology investment. That period left the council's digital infrastructure in uneven shape. The planning portal at gosford.com.au — the public-facing address that redirects through to council's development tracker — still reflects a legacy data architecture that predates the administration period. Several property files in the Gosford CBD precinct, particularly around the Kibble Park and Baker Street corridor where the renewal project is most active, contain image sets that have never been rationalised since the 2016 merger of Gosford City Council and Wyong Shire Council created the current entity.

The local fix — and the obstacles

Council's 2025–26 Operational Plan included a line item for digital records management improvement, though the plan does not specify a deduplication program by name. The broader digital transformation agenda sits within the council's ICT strategy that was refreshed following the administration period. Progress has been incremental. Staff at the Wyong administration building on Hely Street and the Gosford civic precinct on Mann Street both work from the same centralised system, but inconsistent file naming conventions introduced during the merger have made automated deduplication more complex than in councils that have operated under a single system for longer.

For residents and developers, the practical consequence is delay. A straightforward knock-down rebuild application in Woy Woy or a dual-occupancy proposal in Tuggerah that triggers a cross-reference check against heritage or flood overlay maps can stall when the underlying imagery is ambiguous. Solicitors handling conveyancing on properties flagged for development potential in the Gosford renewal corridor have noted, anecdotally, that due-diligence periods are being stretched to accommodate council data queries.

The clearest path forward, based on what Newcastle and international peers have demonstrated, involves contracting a one-time deduplication pass through a hash-matching tool, then embedding a duplicate-prevention rule into the document upload gateway so the problem does not recur. The cost is modest relative to the productivity gain. With Gosford's development pipeline growing and fast-rail ambitions raising the long-term land value stakes along the corridor, getting the data layer right is less a technical nicety than a basic precondition for the renewal project to function at the pace it has been promised.