Does Perth's future hold urban infill and better public transportation or more suburban sprawl?

The Perth coastline stretches from Mandurah in the south to Yanchep in the north. (ABC Radio Perth: Lorraine Horsley)

Stretching 150km along the coast from Two Rocks in the north to Mandurah in the south, the Perth-Peel metropolitan area's length is starkly visible from space.

Many consider it to be the longest city in the world — although it is not an exact science, and Sochi in Russia also has a claim.