Well, I'm making a map, but having a problem with the terrain.
I changed it all to sand, yet when I stand close to it, This happens.

A green grassy texture appears beneath it.
When I zoom out, it's fine.

Any idea how to stop the grass texture from appearing?
Thanks.
Oh and another quick question, is it possible to make it so that once I dive all the way under the water and touch the ground, I can walk on it as if the water is not there? Without this my map would be kind of boring.
Thanks.