Scale of Perth's urban development revealed with 3D modelling

The scale of Perth's urban development has been revealed, with new ground-breaking imagery of several popular suburbs.

Nearmap's 3D technology shows the coastal suburb of Scarborough, packed full of subdivided blocks and triplex development.

"People are taking advantage of the zoning opportunities and subdividing, and potentially selling off their backyard or building a house out the back and renting it out," real estate expert Damian Collins said.

Ten years of images are held by the Perth-founded company and over the past decade Scarborough, Doubleview and Innaloo have had shrinking backyards.

It's a similar story for the suburb of Belmont, while images of Claremont Oval and Terrace Road in East Perth show a rise in multi-story developments.

"If there are suburbs that are not as developed as much, you can see from the Nearmap imagery, there is space to be developed, so it helps with not only what's happened but planning forward," Nearmap CEO Rob Newman said.

Child play experts are urging parents to think of new ways to interact with their children.

Nature Play's Griffin Longley says just 55 percent of Australian children play outdoors each week.

"There's no doubt that we're living through the most dramatic shift in the experience of childhood in the whole of human history," Mr Longley said.

"A loss of play brings terrible mental health outcomes for kids. rates in anxiety are soaring already."

Even as property prices fall, data from the Urban Development index shows a steady increase in the cost of land.

The average lot size a decade ago was approximately 490 square metres and average price almost $470 per square metre.  Since then lot sizes have been shrinking and the price of land has been climbing.

In 2015, properties were on average 100 square meters smaller than 2009 but the cost had risen by 28 percent.

The average lot size now is 373 square metres the cost $621 per square metre.

"In the long run you're not going to see those big blocks anymore because there's just not the demand," Mr Collins said.

"We will continue to see it there's better design guidelines that have come out in the last 12, 18 months to better regulate and get better outcomes for people."