2D plot with 3D data

hi,i'm newbie for Matlab.In my task,i have 256 number of x,y values. Each coordinate(x,y) has it own z value(intensity).The value of z was increase from left to right(x axis) but not increase uniformly.i would like to represent it by showing the z value in boundary,such as z=1-2,2,3,...is that possible?

Thanks for solving my problem.i can explain further if anything unclear above.

Regard. Sim.

Answer 1

[Jan]

You did not specify this, but I guess, that you want to create the output as a string.

% Test data (do they match your needs??):
z = floor(cumsum(rand(256, 256) * 2));
minz = min(z, 1);
maxz = max(z, 1);
minEQmax = (minz == maxz);
C = cell(1, 256);
for i = 1:256
  if minEQmax(i)
    C{i} = sprintf('%d,', minz(i));
  else
    C{i} = sprintf('%d-%d,', minz(i), maxz(i));
  end
end

Str = ['z = ', cat(2, C{:})];
Str(end) = [];  % Remove trailing comma

[sim keng hei]

what i mean is i have 256 number of coordinate(points) on plot,each coordinate has its own intensity(z value).so, 1 would like to put the z value in category(divide by line/contour).The task is below:

http://www.scribd.com/doc/50446665/Doc1?secret_password=owuenlb7u9qol0dl9gi

I want to draw the line with 7,6,5,....

Can Matlab do that?

I really hope u can help me to solve it.i being searching the net for few days already.

Answer 2

[Matt Tearle]

You want a contour plot? Given that it sounds like you have vectors of data:

% Make some fake data
x = rand(256,1)*4-2;
y = rand(256,1)*4-2;
z = x.*exp(-x.^2-y.^2);
% Put data onto a grid
[qx,qy] = meshgrid(linspace(min(x),max(x)),linspace(min(y),max(y)));
F = TriScatteredInterp(x,y,z);
qz = F(qx,qy);
% Make contour plot
contour(qx,qy,qz)

To get specific contour levels, you can do:

contour(...,<vector of levels>)

Answer 3

[sim keng hei]

Thank you.I already solved my problem by using the surface fitting tools.I manage to get the contour line to for my plot.