MATLAB: Average data along z

averagemultidimensional arrayrepeat values

I have data at given xyz points (i.e. locations). For each xy pair, there are multiple z values. I'd like to average the data along the z dimension. In other words, go from 3D+Value to 2D+AveragedValueAlongZ. Is there a fast way to do this (i.e. not needing loops)? Thanks in advance.

Best Answer

[uxy, ~, uidx] = unique([x(:), y(:)], 'rows');
avgv = accumarray(uidx, v(:), [], @mean);
output = [uxy, avgv];

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MATLAB: How to plot color indication on the points in 2D and 3D

pointsize = 20;
scatter3(x(:), y(:), z(:), pointsize, intensity(:));

You can take subsets of the data for particular z, if you want. For example

idx = z == 16;   %watch out for floating point comparisons if the values are not integers!
scatter3(x(idx), y(idx), z(idx), pointsize, intensity(idx));

MATLAB: Different z values for one x y coordinate

%%looking for unique xy values
      uniCoord=unique(data(:,1:2),'rows');
      uniCoord(:,3:12)=NaN;
%%writing for each xy value in column
% 3-9 all corresponding z values
% 10 amount of corresponding z values
% 11 median of z values
% 12 mean of z values
    for i =1:size(uniCoord,1)
        A=(data(:,1)==uniCoord(i,1)&data(:,2)==uniCoord(i,2));
        B=data(A,3)';
        uniCoord(i,3:2+size(B,2))=B;
        uniCoord(i,10)=size(B,2);
        uniCoord(i,11)=median(uniCoord(i,3:2+size(B,2)));
        uniCoord(i,12)=mean(uniCoord(i,3:2+size(B,2)));
    end

Best Answer

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MATLAB: How to plot color indication on the points in 2D and 3D

MATLAB: Different z values for one x y coordinate

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