Why am I getting redundant legend (group) icon colors when utilizing the gscatter command?

Hi. I’m attempting to color code the legend (group) entries in a group scatter plot using the following code:

% Clear out all workspace variables and the command window
clear all;
clc;

% Set values for OATTs and IDs
OATT = [8;10;12;14;16;18;20];
ID = [1;2;5;6;7;1;8];

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

% Setup cases for legend
for idx = 1:size(ID, 1)
          switch ID(idx)
              case 1
                  LegCol{idx} = 'Wild-1';
                  color{idx} = [1 0 0]; % red
              case 2
                  LegCol{idx} = 'Jets-2';
                  color{idx} = [0 1 0];  % green
              case 3
                  LegCol{idx} = 'Kings-3';
                  color{idx} = [0 1 1]; % cyan
              case 4
                  LegCol{idx} = 'Sharks-4';
                  color{idx} = [1 0 1]; % magenta
              case 5
                  LegCol{idx} = 'Ducks-5';
                  color{idx} = [1 1 0]; % yellow
              case 6
                  LegCol{idx} = 'Coyotes-6';
                  color{idx} = [0 0 0]; % black
              case 7
                  LegCol{idx} = 'Canucks-7';
                  color{idx} = [0 0 1]; % blue
              case 8
                  LegCol{idx} = 'Blackhawks-8';
                  color{idx} = [0.8 0.8 0.8]; % grey
              case 9
                  LegCol{idx} = 'Blues-9';
                  color{idx} = [1 0.55 0]; % orange
              case 10
                  LegCol{idx} = 'Predators-10';
                  color{idx} = [0.58 0 0.83]; % violet

            end

end

% Transpode LegCol and color data for legend use
Legend_Nomenclature = transpose(LegCol);
Color_Nomenclature = transpose(color);
New_Colors = cell2mat(Color_Nomenclature);

% Find unique elements of ID and use the returned index
% vector n as the y-axis value in the gscatter plot
[~, m, n] = unique(ID);
ID_Index = n;

figure('Name', 'Gscatter Test');
h = gscatter(OATT, ID_Index, Legend_Nomenclature, New_Colors, 'o', 15, 'on');
for n = 1:length(h)
    set(h(n), 'MarkerFaceColor', New_Colors(n, :));
end

At this time, I have to apologize for the lack of an image as I’m unable to embed it in this question.

However, when I run the above code, the group scatter plot is created - as expected - with a single exception. For unknown reasons the last group of data (with ID = 8) shows up as a red dot on the plot and within the legend. It should in fact be grey.

What could be the cause of this?

Answer 1

[Tom Lane]

The gscatter function as a separate legend entry for each group. Your group, as given by the Legend_Nomenclature variable, is the same for the points at (8,1) and (18,1).

You might just want to use the plot function if you intend for each point to have a separate legend entry.

[Brad]

Tom, I believe you are correct. As hard as I try to get the legend correct using the gscatter function, it just won't do it. The plot function does work fine. Thanks for taking a look at this.