How to add black isolines for f(x,y) = -1, 0, 1

Hi ,

I have f(x,y) and I want to add black isolines for f(x,y) = -1, 0, 1. How can I do it?

Thanks

Answer 1

[Steven Lord]

Use the contour or contour3 functions.

[Faraz Ali]

I checkd it but my question is how can I set value of f(x,y) = -1,0,1 for contour? Can you give me an example of it ?

[Steven Lord]

[x, y, z] = peaks;
surf(x, y, z)
shading interp
hold on
contour3(x, y, z, [-1, 0, 1], 'k')

[Faraz Ali]

Is the default color of isolines black ?

I have f(x,y) = sinx+cosy ( for example). I have to assign f(x,y) to "z" variable for contour? Does it work in the same way for adding black isolines?