[Grim_]

To return the solid Z coordinate based off of two givens, X and Y, you'll need to download the MapAndreas plugin. You can find it's download and how to use it all on its page, here: https://sampforum.blast.hk/showthread.php?tid=120013

There is also another version out, a revision of another user, here: https://sampforum.blast.hk/showthread.php?tid=275492