[R] plot one levelplot over another

[Waichler, Scott R]

Hi, I am using levelplot() to plot a primary response surface, z1.  I wish to write a custom panel function that will let me plot another surface z2 = f(x,y) over z1.  The second surface z2 is either NA or 1, and at locations where z2 = 1, I will use a color with low alpha to let the the z1 surface show through.  How can I do this?

Regards,
Scott Waichler
Pacific Northwest National Laboratory
Richland, WA USA