Landscape visibility mask by texture

Hello
I am wondering if it is possible to use a texture to control the Landscape visibility mask rather than painting.
Also, I can’t seem to paint from the Top View. Is there a restirction to painting from orthographic views?

Bumping this since I just ran into the same problem. On top of it it does not seem possible to paint landscape in Perspective View if you are more than so far away from the landscape. Is it by design or is it a bug?