Why is the legend in my MATLAB code showing only one color for all the items, even though the colors are different in the parallel coordinates graph?

% Define colors for each alphaclass

colors = {[1 0 0], [0 1 0], [0 0 1], [1 0 1]}; % RGB values for red, green, blue, magenta

alphaClasses = repelem(1:4, numImages/4);

% Create a parallel coordinates plot for the projected images

figure;

for i = 1:length(alphaClasses)

line(1:numComponents, projectedImages(i,:), 'Color', colors{alphaClasses(i)});

end

xlabel('AB');

ylabel('CD');

title('Parallel Coordinates Plot of Projected Images');

legend('ab', 'cd', 'ef', 'gh', 'Location', 'northeast');

Answer 1

[Dyuman Joshi]

Because there is only one line in the plot, as the plot is getting overwritten in each iteration. You need to use the command

"hold on" to retain all the plots in the same figure.

figure
hold on
for i = 1:length(alphaClasses)
    line(1:numComponents, projectedImages(i,:), 'Color', colors{alphaClasses(i)});
end
%use hold off after the loop if necessary