MATLAB: How to use the Meshgrid and surf functions

MATLABmeshgridsurf

I need to create a script that uses the meshgrid and surf functions to generate a 3-D surface plot of the function z = cos(sqrt(x^2 + y^2)) in the domain −7 ≤ x ≤ 7 and −7 ≤ y ≤ 7 (use a step size of 0.1). How would you do this?

Best Answer

v = -7:0.1:7;
[x, y] = meshgrid(v, v);
z = cos(sqrt(x.^2 + y.^2));
surf(x, y, z, 'edgecolor', 'none')

Related Solutions

MATLAB: How to plot x^2+z^2=9 above the xy plane and between y=-1 and y=2

How about:

syms x y z;
[x,y]=meshgrid(-10:1:10);
z = abs(sqrt(9-x.^2));
surf(x,y,z);
ylim([-1 2])

MATLAB: Meshgrid

I assume that x and y have the same values as x1 and y1, but in a different order. You could do a search for each pair (x1,y1), but it's faster to sort the coordinates and then reshape Z. Here is an example with an actual image to give you the idea:

%%Set up the problem
load mandrill
Z = X; %rename image
nrows = size(Z,1); ncols = size(Z,2);
[x1,y1] = meshgrid(1:nrows,1:ncols);
x = x1(:); y = y1(:); Z = Z(:);
% Scramble the elements.
index = randperm(numel(Z));
x = x(index); y = y(index); Z = Z(index);
%%Now the problem is set up, unscramble x and y and then reshape Z.
xy = [x y];
[~,index] = sortrows(xy,[1 2]);
x = x(index); y = y(index); Z = Z(index);
Z = reshape(Z,nrows,ncols);
image(Z)

Of course, if x and y were originally obtained from a process like that in the previous cell, you won't need to sort.

Best Answer

Related Solutions

MATLAB: How to plot x^2+z^2=9 above the xy plane and between y=-1 and y=2

MATLAB: Meshgrid

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