How to find all 0 values

Hi I have plotter a pcolor and then surf plot of X,Y,Z. X and Y is the latitude and longitude and Z is elevation. I want to add a black contour line at elevation =0 but cant seem to figure it out (ive tried using contour3) does anyone know how to do this? or know how to find all elevation =0 values maybe using a find loop so i can plot this on the same figure? thanks in advance!

[Shashank]

This might be the issue:

How can I place a linear plot on top of a surface plot?

Answer 1

[KSSV]

Use pcolor and on this use contour to plot your elevation heights.