Is it possible to get MATLAB to automatically associate legend icon colors with the applicable data?

I’m attempting to hard code colors to data in a 2D plot using the following code;

% Clear out all variables from the Workspace and the Command Window

clear all;
clc;

% Variables for plotting
To_Time = 58560;
Time_Tag = [58568.4; 58571.8; 58573.4; 58574.4; 58577.4; 58579.8; 58582.4; 58584.1; 58587.6; 58589];
ID = [10; 2; 3; 4; 10; 6; 7; 2; 10; 2];
Measured_Data = [1.25; 2.31; 3.3; 4.9; 5.7; 6.7; 7.1; 8.6; 9.1; 10];

% Calculate TALO times for all IDs
TALO_Time = Time_Tag - To_Time;

% Preallocate 
LegCol = cell(1, size(ID, 1));
color = cell(1, size(ID, 1));

% Setup cases for auto legend generation
for idx = 1:size(ID, 1)
          switch ID(idx)
              case 1
                  LegCol{idx} = 'Data-1';
                  color{idx} = [1 0 0]; % red
              case 2
                  LegCol{idx} = 'Data-2';
                  color{idx} = [0 1 0];  % green
              case 3
                  LegCol{idx} = 'Data-3';
                  color{idx} = [0 0 1]; % blue
              case 4
                  LegCol{idx} = 'Data-4';
                  color{idx} = [1 0.55 0]; % orange
              case 5
                  LegCol{idx} = 'Data-5';
                  color{idx} = [1 0 1]; % magenta
              case 6
                  LegCol{idx} = 'Data-6';
                  color{idx} = [0 1 1]; % cyan
              case 7
                  LegCol{idx} = 'Data-7';
                  color{idx} = [0 0 0]; % black
              case 8
                  LegCol{idx} = 'Data-8';
                  color{idx} = [1 1 0]; % yellow
              case 9
                  LegCol{idx} = 'Data-9';
                  color{idx} = [0.58 0 0.83]; % violet
              case 10
                  LegCol{idx} = 'Data-10';
                  color{idx} = [0.72 0.53 0.04]; % gold

            end

            % Transpode LegCol and color data for legend use
            Legend_Nomenclature = transpose(LegCol);
            New_Colors = transpose(color);

            % Setup the TALO Plot
            h = plot(TALO_Time(idx), Measured_Data(idx), 'o', 'Color', New_Colors{idx}, 'MarkerSize', 14);
            set(h, 'MarkerFaceColor', New_Colors{idx});
            hold all;

end

AA = unique(Legend_Nomenclature);
hleg = legend(AA, 'Location', 'NortheastOutside');

The following plot is produced;

While the plotted data is correct, the corresponding legend icon colors are not. I’m getting;

Gold Data-10

Green Data-2

Blue Data-3

Orange Data-4

Gold Data-6 (should be cyan)

Cyan Data-7 (should be black)

Is there a way to automatically associate legend icon colors with the applicable data?

Thank you.

Answer 1

[Sean de Wolski]

Legend has the ability to pass in specific line objects to be legend-ized. Here, you throw away those lines in the for-loop. Instead, store them and legend-ize the applicable unique ones from AA:

 % <snip>
      % Store h(idx), set(h(idx),...
      h(idx) = plot(TALO_Time(idx), Measured_Data(idx), 'o', 'Color', New_Colors{idx}, 'MarkerSize', 14);
    set(h(idx), 'MarkerFaceColor', New_Colors{idx});
    hold all;
end

%%Grab unique sources and legend
[AA,idxu] = unique(Legend_Nomenclature);
hleg = legend(h(idxu),AA, 'Location', 'NortheastOutside');

[Brad]

Sean, thank you.