MATLAB: Plotting Contours at Specfic Points (x,y)

Question

I'm currently producing a contour plot using

contour(x,y,z)

However, I would like to specify some additional contour lines to the ones provided. I understand that I can use contour(x,y,z,v) where v is some vector containing values of the contour levels I would like but I don't really want to use this since I don't know exactly the levels.

Instead is it possible to plot the contour that goes through a specific point (x,y)?

Thanks.

Answer 1

You can overplot a second contour with a single, specific value for the contour, optionally specifying parameters like line width to make it obvious:

contour(x,y,z)
hold on
lev = z(n,m); % find the value you want in z
contour(x,y,z,lev,'Linewidth',2);