A "discrete" contour plot

Question

Brooke 2012-4-15

If M(i,j) is a matrix,

How might I plot a contour plot where the (i,j) point on the x,y-plane has altitude M(i,j)?

What I did was

x = 1:1:imax;

y = 1:1:jmax;
 
[x,y] = meshgrid(x,y);
z=M;
[c,h] = contour(x,y,z,100);
clabel(c,h,'manual');

But it doesn't seem to be right…

(If the plotting bit is right, then there must be something else the wrong with the program!)

Walter Roberson 2012-4-15

It isn't a good idea to overwrite x and y with meshgrid(x,y), in the sense that it is confusing to the reader.

Answer 1

Wayne King 2012-4-15

When you say "discrete" contour plot, do you mean something like

   z = abs(round(peaks(5)));
   bar3(z,0.3);

Brooke 2012-4-15

@Wayne: No, I just meant that the "data points" are given at discrete points. Sorry about the ambiguity... Nice bar chart, btw.