This is as blank a canvas as you get.

IT WOULD present the kind of opportunity that urban planners only see in their dreams — a 400-acre tract of land, with skyline views of Manhattan, that could be turned into anything imaginable.

The potential closure of Rikers Island has ignited the imaginations of city planners, developers, park advocates and transportation experts.

“The possibilities really are endless,” said David Schwartz, co-founder of development firm Slate Property Group. “You really have never had a piece of property in New York City that is this large that you can do almost anything with. This is as blank a canvas as you get.”

But the remote land mass located in Queens would pose a host of challenges to anyone wishing to transform it into an idyllic residential community.

Its proximity to LaGuardia Airport means skyscrapers would be off the table. Because of flight paths over the island, buildings would be restricted to no more than 15 stories inland and five stories along the eastern and southern edges.

A developer would also likely need to install double windows to deaden the sound of the jets roaring overhead.

The island’s soil presents even more pressing — and expensive — problems, according to experts tasked with analyzing the land.

Because Rikers was built on a landfill, some parts of the island are unsteady and others contain significant amounts of toxic methane gas.

Experts say that building on top of the contaminated soil would be a costly and challenging endeavor that would require installing a vapor barrier to block the methane and anchoring the foundation into solid ground beneath the waste.

“The cost of building a residential unit on Rikers Island would be roughly double a comparable unit elsewhere in the city,” said an urban design consultant who’s been examining the site.

Jim Venturi, a self-taught