Definition of "canyonland"

But I soon realized that whoever described the city as a concrete canyonland had his topography all wrong.

2009 March 8, Christopher Solomon, “Mountain Man”, in New York Times‎

The Kotsoteka Comanche lived mostly along the Canadian River, where the Llano ended and the dry plains turned into grassy canyonlands.

2013, Philipp Meyer, The Son, Simon & Schuster, published 2014, page 94