MATLAB: Adding appropriate legend data

legend

Using Matlab 2009a I created a plot that contains data from multiple sources. The sources can be input as either individual directories or as multiple sets of directories.

In the case of plotting from individual directories, the legend is simply the names of the individual directories.

In the case where multiple sets of directories are plotted (each directory in a set with the same color), I would like to see a legend like "set-1 blue, set-2 red, etc". This appears to be a problem, as legend will align each character set given with the color of the next line drawn, not the set as a whole. The result is of course that the legend contains the same colors for all sets (at least while the number of entries in the legend is smaller than the number of entries in the first set).

Is there any way to overcome this?

Best Answer

If you pass a vector of graphic handles as the first parameter to legend(), then the legend box produced will reflect those handles. When the handles are of line() or lineseries() objects (such as plot() produces), then legend() will use the line color and line appearance and line marker shape and color, to create the line used in the legend box.

Related Solutions

MATLAB: Change Color of Specific Legend Text (not all text)

Instead of doing all that, you can use LaTeX to change the color of the legend text. Let's take a simple example.

x = [1 2 3 4];
y = [2 4 6 8];
z = [2 3 4 5];
plot(x, y, x, z);
legend('{\color{green}y vs x}', '{\color{blue}z vs x}');

This would give you the following graph.

You can even have multiple colors in the same text. For instance.

legend('{\color{green}C}{\color{red}O}{\color{orange}L}{\color{black}O}{\color{gray}R}', '{\color{blue}z vs x}');

The above would give you the following graph.

Hope this helped. :)

MATLAB: Plot tools：add data color

If you want to make the line black at the time of plotting, add the argument 'k' to the plot command.

Example:

figure;
x = 0:0.1:10;
y = sin( x );
plot( x , y , 'k');

If you have a line that is blue and you want to make it black, you can use findobj to get the handle of the blue line and then set its color property value to black manually.

Example:

% plot something
figure;
x = 0:0.1:10;
y = sin( x );
plot( x , y  , 'Blue' );
% the color values for blue and black
blue  = [ 0 0 1 ];
black = [ 0 0 0 ];
% get the handle for the blue line
hline = findobj( gca , 'color' , blue );
% Set the line's color property value to black 
set( hline(1) , 'color' , black )

Best Answer

Related Solutions

MATLAB: Change Color of Specific Legend Text (not all text)

MATLAB: Plot tools：add data color

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