Plotting a graph with different colors depending on different vectors

Hi! I would like to plot a graph that has different colors depending on different vectors. I want to sum up all vectors but still be able to tell them apart by showing them in different colors. There are 4 vectors with 8760 values each. How can I do this?

Answer 1

[Dave B]

You can plot multiple vectors by either:

• passing them into plot as a matrix, plot will make a line for each column of the matrix if you don't specify x values. If you do specify x values plot will match up the appropriate dimension of the matrix.
• calling plot multiple times, making sure to specify hold on some time before the second call

You can specify the color explicitly for each line, or let MATLAB select from the current color order. You can change the colors in that list using the colororder function, and you can change the mapping of each color to its index into the color order using the SeriesIndex property.

Example data as you described it

y1=randn(8760,1);
y2=randn(8760,1)+5;
y3=randn(8760,1)+10;
y4=randn(8760,1)+15;

Plot of the four variables:

plot([y1 y2 y3 y4])

You mentioned the sum:

hold on
thesum = sum([y1 y2 y3 y4],2);
plot(thesum)

A legend to show what the colors refer to

legend(["y1" "y2" "y3" "y4" "sum"])

Alternate, use hold on:

figure
plot(y1)
hold on
plot(y2)
plot(y3)
plot(y4)

Change the colors using colororder:

figure
plot([y1 y2 y3 y4])
colororder([1 0 0; 0 1 0; 0 0 1; 0 1 1])

Specify the colors explicitly for each line:

figure
plot(y1,'black')
hold on
plot(y2,'red')
plot(y3,'blue')
plot(y4,'green')

Answer 2

[DGM]

Depends what your data is and what you actually want. Are you thinking of an area plot?

n = 6;
A = 0.5*rand(n,1) + 0.5;
B = 0.5*rand(n,1) + 0.5;
C = 0.5*rand(n,1) + 0.5;
D = 0.5*rand(n,1) + 0.5;
S = A+B+C+D;

ha = area([A B C D]);
hold on; 
hp = plot(S,'linewidth',2);

legend([ha hp],{'A','B','C','D','A+B+C+D'})

That only really makes sense if each vector is always positive-valued.