Specify Different Sets of Colors and Line Styles

The colors MATLAB selects come from the axes ColorOrder property, which contains a three-column matrix of colors specified as RGB triplets. An RGB triplet is three-element vector containing the intensities of the red, green, and blue components of a color. The intensities must be in the range [0, 1].

If you plot multiple lines, the first line uses the first color in the ColorOrder matrix, the second line uses the second color, and so on. Eventually, the colors repeat if the plot has more lines than rows in the matrix. This code creates several line plots that use the default color order. The first line is the top-most line. Because the default ColorOrder matrix has seven rows, the colors repeat after the seventh line.

plot([9 10 11 12])
hold on
plot([8 9 10 11])
plot([7 8 9 10])
plot([6 7 8 9])
plot([5 6 7 8])
plot([4 5 6 7])
plot([3 4 5 6])
plot([2 3 4 5])
plot([1 2 3 4])
hold off
legend("Location","northeastoutside")

You can change the colors in either of two ways:

Create a new matrix containing the RGB triplets for red, green, and blue. Then set the ColorOrder property to that matrix. The plot updates immediately with the new colors.

mycolors = [1 0 0; 0 1 0; 0 0 1];
ax = gca; 
ax.ColorOrder = mycolors;

MATLAB also cycles through different line styles in addition to colors. By default, there is only one line style (a solid line). To specify additional line styles, set the LineStyleOrder property of the axes. For example, this code specifies three line styles. The updated plot cycles through all the colors with one line style before displaying the next line style.

mylinestyles = ["-"; "--"; "-o"];
ax.LineStyleOrder = mylinestyles;

Specify Cycling Order of Colors and Line Styles

Since R2023a

When you use multiple colors and line styles, you can specify whether the plot cycles through all line styles before, after, or at the same time as the colors by setting the LineStyleCyclingMethod property. This property can have one of three values:

Plot four lines. Set the LineStyleOrder property to three line styles, and set the ColorOrder property to three colors by passing an array of three hexadecimal color codes to the colororder function. Then add a legend.

% Plot four lines
plot([4 5 6 7])
hold on
plot([3 4 5 6])
plot([2 3 4 5])
plot([1 2 3 4])
hold off

% Set the line style order and color order
ax = gca;
ax.LineStyleOrder = ["-"; "--"; "-o"];
colororder(["#8040E6";"#1AA640";"#E68000"])
legend("Location","northeastoutside")

By default, the plot cycles through all the colors with the first (solid) line style before it displays the next (dashed) line style. Because there are three colors, only two of the line styles are used in the four-line plot.

If you want more of your lines to be distinct in both color and line style, use the "withcolor" option and specify an equal number of colors and line styles. For example, change the LineStyleCylingMethod of the preceding plot to "withcolor". The updated plot cycles through the colors and the line styles at the same time.

ax.LineStyleCyclingMethod = "withcolor";

Group Your Data by Color or Line Style

Since R2020a

To group related lines (or other plot objects) together visually, set the SeriesIndex property of each object that you want to receive the same visual treatment to the same number. The SeriesIndex property indexes into the ColorOrder and LineStyleOrder arrays according to the value of the LineStyleCyclingMethod property. Thus, different objects with the same SeriesIndex value use the same color (and line style, if applicable).

For example, plot two sets of 50 scattered points.

x = 1:50;
meas1 = 0.25*x + randn(1,50);
scat1 = scatter(x,meas1);
hold on
meas2 = 0.5*x + randn(1,50) + 5;
scat2 = scatter(x,meas2);

Calculate a fit line for each set of points using the polyfit and polyval functions. Then add each fit line to the plot.

% Calculate fit lines for each set of measurements
p1 = polyfit(x,meas1,1);
y1_fit = polyval(p1,x);
p2 = polyfit(x,meas2,1);
y2_fit = polyval(p2,x);

% Plot fit lines
fitline1 = plot(x,y1_fit);
fitline2 = plot(x,y2_fit);
hold off

The scatter plots and fit lines are all different colors. The reason is that MATLAB selects a new color from the ColorOrder matrix for each new plot you add to the axes.

Match the color of each fit line with its associated scatter plot. Set the SeriesIndex property of each line to the same value that the associated scatter plot has.

fitline1.SeriesIndex = scat1.SeriesIndex;
fitline2.SeriesIndex = scat2.SeriesIndex;

This relationship persists even if you change the colors in the ColorOrder matrix. For example, change the colors to purple and green by calling the colororder function.

colororder([0.5 0.25 0.90; 0.10 0.65 0.25])