Perth's Duplicate Image Problem: How the City Stacks Up Against Singapore, Calgary and Cape Town

Perth's local governments and real estate data managers are working through a mounting backlog of duplicate property images embedded across planning databases, council portals and online listing archives — a problem that has quietly compounded over a decade of rapid digitalisation and is now costing agencies measurable time and money to untangle.

The issue is not unique to Western Australia, but the scale of Perth's housing boom makes it acute here. The State Government's Metronet rail expansion has triggered a wave of transit-oriented development proposals across suburbs stretching from Yanchep in the north to Thornlie in the south-east, each generating hundreds of new planning submissions loaded with photographs. Without consistent deduplication protocols, those images pile up across multiple systems — council GIS layers, the Department of Planning Lands and Heritage's ePlanning portal, and third-party aggregators like realestate.com.au and Domain.

What Other Cities Are Doing

Singapore's Urban Redevelopment Authority began mandating a centralised image hash-checking system for all development applications lodged through its Integrated Land Use Planning platform in 2023. The city-state publishes compliance metrics annually. Calgary, facing a similar problem after its own suburban expansion corridor opened along the Green Line LRT route, contracted a private data hygiene firm in early 2024 to audit roughly 340,000 planning images held across three separate municipal databases. Cape Town's City Improvement Districts — particularly those managing the Atlantic Seaboard and the Woodstock regeneration precinct — adopted open-source perceptual hashing tools that year after duplicate images caused delays in heritage assessments for at least six development sites.

Perth, by contrast, has relied largely on individual agencies setting their own standards. The City of Perth, which manages the CBD and surrounding precincts including Northbridge and East Perth, uses the Pathway software platform for development tracking. The City of Stirling — one of the state's largest local governments by population, covering suburbs from Scarborough to Balcatta — runs a separate system. Neither council's public documentation currently describes a formal deduplication policy for submitted imagery, though both have IT upgrade programs underway as part of broader digital transformation spending.

Why It Matters for Housing and Planning

Duplicate images create concrete administrative friction. When a planner pulls site photos to assess a heritage overlay or a bushfire attack level classification, finding five near-identical images of the same elevation wastes time and, in some documented cases in other jurisdictions, has contributed to errors when images from the wrong version of a site were inadvertently carried forward into reports.

Western Australia's housing market is running hot. Perth's median house price reached record levels in the first half of 2026, with CoreLogic data showing sustained annual growth that has pushed transaction volumes — and therefore listing photo volumes — well above long-term averages. Every sale generates multiple rounds of imagery: agent listing photos, council inspection images, bank valuation photos, and in some cases separate heritage or environmental survey photographs, all potentially entering overlapping databases.

The Real Estate Institute of Western Australia has previously flagged data quality as a systemic concern in submissions to state government reviews of property data infrastructure, though the organisation has not published a specific position on image deduplication to date.

AUKUS-linked development around HMAS Stirling on Garden Island adds another layer. Defence contractors bidding on facility upgrades must lodge imagery with both Defence Housing Australia and relevant state planning bodies, creating parallel archives with no current reconciliation requirement.

For property professionals and councils watching how this plays out, the practical near-term step is straightforward: before the next major ePlanning portal upgrade — which the Department of Planning Lands and Heritage has flagged as part of its broader digital service reform — agencies should conduct an image audit against a standard perceptual hash library. Singapore and Calgary both found their initial audits took between three and five months for databases of comparable size to Perth's. Starting that work now, before the Metronet development pipeline fully matures, is considerably cheaper than retrofitting clean data into a system already carrying years of duplicates.