Plot 3d plot with different colors depending on the X and Y combination

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I am plotting a 3D plot, (X,Y,Z).
X and Y are indexes from 1 to 44.
I want that the bar plot color of Z depands on the values of X and Y.
For example:
when X =1 and Y = 20 so the Z bar has to be in color green
when X =10 and Y = 40 so the Z bar has to be in color red
when X =42 and Y = 40 so the Z bar has to be in color blue
The array combination of X and Y are stored in varriable IN, OUT.
for example
IN=[1 5 6 7 8 9 2 10....] (22 values)
OUT=[20 44 21 ....] (22 values)

Answers (2)

Cris LaPierre
Cris LaPierre on 14 Apr 2023
Edited: Cris LaPierre on 14 Apr 2023
Here's the example from that page.
Z = magic(5);
b = bar3(Z);
colorbar
for k = 1:length(b)
zdata = b(k).ZData;
ix=isfinite(zdata(:,1));
zdata(ix,1)=zdata(ix,2);
b(k).CData = zdata;
b(k).FaceColor = 'flat';
end
  12 Comments
Tesla
Tesla on 17 Apr 2023
I tried to write this code, but not working for me, i tried many changes no luck
color_matrix = zeros(44, 44);
color_matrix(strcmp(matrix, 'D')) = 1;
color_matrix(strcmp(matrix, 'S')) = 2;
color_matrix(strcmp(matrix, 'DS')) = 3;
color_matrix(cellfun('isempty', matrix)) = 4;
[X, Y] = meshgrid(1:44, 1:44);
bar_colors = [0 0 0; 0 0 1; 0 1 0; 1 1 1];
figure;
ax = gca;
hold(ax, 'on');
for i = 1:numel(X)
x = X(i);
y = Y(i);
z = Z(i); %% here where my data for Z are saved
color_idx = color_matrix(i);
h = bar3(ax, y, z, 1);
zdata = ones(6 * size(z, 2), size(bar_colors, 2));
zdata(:,:) = repmat(bar_colors(color_idx, :), 6 * size(z, 2), 1);
set(h, {'ZData'}, {zdata});
set(h, 'XData', x);
end
hold(ax, 'off');
view(ax, 3);
xlabel(ax, 'X-axis');
ylabel(ax, 'Y-axis');
zlabel(ax, 'Z-axis');
title(ax, '3D Bar Plot');

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Daniel
Daniel on 14 Apr 2023
You're interested in creating a bar chart where you can individually control the color of each bar, correct?
If so, you can start by creating a normal bar chart and collecting the handle, like so:
b = bar(0:5,6:-1:1)
b =
Bar with properties: BarLayout: 'grouped' BarWidth: 0.8000 FaceColor: [0 0.4470 0.7410] EdgeColor: [0 0 0] BaseValue: 0 XData: [0 1 2 3 4 5] YData: [6 5 4 3 2 1] Show all properties
Once you have the handle b, you can set the FaceColor property to 'flat'. This allows you to control the color of each bar individually with the CData property. The CData property has one row per bar, and one column per color.
% Colors are specified as [R G B], where each base color is in the range 0
% to 1.
redColor = [1 0 0];
greenColor = [0 1 0];
blueColor = [0 0 1];
grayColor = [0.5 0.5 0.5];
% You can read the X and Y data of each bar element through XData and
% YData. You can modify the color by changing CData.
% YData is a vector of the same length as your input.
% CData is a matrix with one row per input and one column per color.
b.FaceColor = 'flat';
for idx=1:length(b.XData)
if b.YData(idx) == 1 % Extract elements from YData
b.CData(idx,:) = redColor; % Extract rows from CData
elseif b.YData(idx) == 3
b.CData(idx,:) = greenColor;
elseif b.YData(idx) == 5
b.CData(idx,:) = blueColor;
else
b.CData(idx,:) = grayColor;
end
end

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