MATLAB: Convert xy Coordinates to Matrix

coordinatesmatrixvector

I have an xy coordinates positions (100×2) and another z vector (100×1) with values corresponding to each xy coordinate. How can I make a matrix of the coordinates with the position of each coordinate having the corresponding z value? Thanks!

Best Answer

after John's comment in Image Analyst's answer:

out = accumarray([x(:),y(:)],z(:),[10 10]);

out = zeros(10);
out(sub2ind(size(out),x,y)) = z;

Related Solutions

MATLAB: Using surf and pol2cart on matrix

The matrix you have is actually the ‘Z’ matrix. You need to create separate radius and angle matrices of the same size (use ndgrid or meshgrid for that, and be aware that their outputs are not the same), then use all three of those matrices as arguments to pol2cart. You will likely need to experiment a bit.

See: Plotting an exponential exp(-x), in 3D? for an example.

EDIT — (25 Jun 2020 at 23:17)

Using code example, try something like this:

Z = rand(512,1000);                                 % Create 'Z'
angles = linspace(0, 2*pi, size(Z,2));
radii = linspace(1, 10, size(Z,1));
[A, R] = meshgrid(angles, radii);
[X, Y, Z] = pol2cart(A, R, Z);
figure
surf(X, Y, Z)
shading('interp')
grid on

MATLAB: Finding maximum y value for the same x values and corresponding z values

Use the ismember function with the 'rows' option:

xy = [1 5
1 7
1 9
2 8
2 22
2 11
5 5
5 10
5 20];
z = [1
9
7
8
6
5
3
2
4];
xyz = [xy z];
[uv,~,idx]  = unique(xy(:,1)); %what do they correspond to?
xmax = accumarray(idx,xy(:,2),[],@max); %build matrix
Result = [uv xmax];
[~, ix] = ismember(Result(:,1:2), xyz(:,1:2), 'rows');
All_Columns = xyz(ix,:)
All_Columns =
       1     9     7
       2    22     6
       5    20     4

Best Answer

Related Solutions

MATLAB: Using surf and pol2cart on matrix

MATLAB: Finding maximum y value for the same x values and corresponding z values

Related Question