How to remove X and Y data which corespond to a Z criteria?

Question

I have an 3D data stored in variable X, Y, and Z.

The Z value is ranging around from -150.51 to 13.45.

This data is to big but most of them are suppose to be outside my consideration.

How can I create Xnew, Ynew, and Znew that with only Z > -20 data?

NB. I can filter Z by:

Znew = gt(Z,-20)

But it is not corresponding to X and Y any more.

Answer 1

Is this what you want?

ind = Z > -20;
Xnew = X(ind);
Ynew = Y(ind);
Znew = Z(ind);