Cadastre Alignment and Topology Repair

Yarra Valley Water is the largest of Melbourne’s three retail water corporations. Owned by the Victorian Government, it supplies drinking water and sewerage services to more than two million people and around 62,000 businesses across the city’s northern and eastern suburbs. Its territory covers some 4,000 square kilometres, from Wallan in the north to Warburton in the east, and holds more than 20,000 kilometres of water and sewer mains. Every one of those pipes, valves, manholes and connections has a place on the map, and that place is supposed to agree with the cadastre, the register of property boundaries that the rest of the state’s spatial data is built on.

Challenge

Yarra Valley Water had a mountain of infrastructure data that needed checking and correcting. Water and sewer pipes, valves, manholes and connections across the network did not all line up properly against the cadastre. Misaligned infrastructure data is not a cosmetic problem. When a pipe’s position on the map does not match its position on the ground, the topology breaks. Everything built on top of that topology, from network tracing to maintenance planning, breaks with it.

Checking and correcting that data sounds simple in principle. In practice every feature has to be checked one at a time, and there were a great many of them. Yarra Valley Water’s own team already had a full-time job keeping the network running and could not absorb a correction exercise at that scale on top of day-to-day operations. What it needed was sustained capacity, enough hands to power through the backlog without pulling staff off business-as-usual work.

Solution

GIS People brought in a dedicated team to clear the backlog. The team first built the geodatabase that holds Yarra Valley Water’s water and sewer pipeline network data, then went to work on the data itself. Every pipe, valve, manhole and connection was checked against the cadastre and corrected where it did not match. Where connections were wrong, the topology was repaired so that the network connects on the map the way it actually connects in the ground.

It is not glamorous work, but it is exacting work, the kind that is easy to get wrong at speed and expensive to get wrong at scale. Because it ran as a separate, dedicated effort, Yarra Valley Water’s own team stayed on business-as-usual operations throughout, and once the data was aligned and the topology correct, the utility was not left carrying that extra capacity permanently.

Outcomes

• A purpose-built geodatabase holding the water and sewer pipeline network.
• Infrastructure data aligned to the cadastre, so field crews and planners work from a map that matches what is actually in the ground.
• Correct network topology, so the network can be traced, modelled and analysed with confidence because features connect the way the system says they do.
• The backlog cleared by a dedicated team, with no disruption to day-to-day operations and no permanent addition to headcount.

Getting the foundation right does not show up on its own. It shows up in every GIS analysis, maintenance decision and network model built on top of it, with no one left double-checking whether the data can be trusted.

Is a data backlog holding your network back? We bring dedicated teams to clear large-scale cadastre alignment and topology backlogs, without pulling your people off the work that keeps the network running. Talk to GIS People about yours.