This example shows how to highlight contours at particular levels.
Define Z as the matrix returned from the peaks function.
Z = peaks(100);
Round the minimum and maximum data values in Z and store these values in zmin and zmax, respectively. Define zlevs as 40 values between zmin and zmax.
zmin = floor(min(Z(:))); zmax = ceil(max(Z(:))); zinc = (zmax - zmin) / 40; zlevs = zmin:zinc:zmax;
Plot the contour lines.
Define zindex as a vector of integer values between zmin and zmax indexed by 2.
zindex = zmin:2:zmax;
Retain the previous contour plot. Create a second contour plot and use zindex to highlight contour lines at every other integer value. Set the line width to 2.
hold on contour(Z,zindex,'LineWidth',2) hold off