2D plot with 3D data

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sim keng hei
sim keng hei on 10 Mar 2011
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.

Answers (3)

Jan
Jan on 10 Mar 2011
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
  1 Comment
sim keng hei
sim keng hei on 10 Mar 2011
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.

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Matt Tearle
Matt Tearle on 10 Mar 2011
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>)

sim keng hei
sim keng hei on 11 Mar 2011
Thank you.I already solved my problem by using the surface fitting tools.I manage to get the contour line to for my plot.

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