how to do plotting with different colors in same figure?

My sample code is this:

 x=[1:100];
 for i=1:5
 y(:,i)=i*log(x);
 end

This plots 5 different curves of same color.

How to plot each curve with a different color ?

[CPS]

 x=[1:100];
 for i=1:5
 y(:,i)=i*log(x);
 end
 plot(x,y)

This will generate an automatic graph.

[Image Analyst]

This is not a comment so you should put it with the rest of the "Answers" below (so you could get "reputation points" for it if someone "Votes" for it).

Answer 1

[Simon]

Hi!

If you plot like

plot(x,y)

and y is a matrix, you get plots with different color automatically. But you can do something like this to get manual coloring:

colorstring = 'kbgry';
figure(1); cla;
hold on
for i = 1:5
  plot(x,y(:, i), 'Color', colorstring(i))
end

[Ved]

@Simon: Thank You.

Could you please tell what if there are many plots.

Say,20 plots.(i.e., i=20) and also the legend ( say i=1,i=2, ... ,i=20) for 20 plots.

[Simon]

Hi!

Define your colors as RGB values like

colorspec = {[0.9 0.9 0.9]; [0.8 0.8 0.8]; [0.6 0.6 0.6]; ...
  [0.4 0.4 0.4]; [0.2 0.2 0.2]};
figure(1); cla;
hold on
for i = 1:5
  plot(x,y(:, i), 'Color', colorspec{i})
end

Mind the '{}' now in the plot command! You may define as many colors as you like.

If you want to have repeating colors (for plots with many lines useful), try

x=[1:100];
for i=1:20
  y(:,i)=i*log(x);
end

colorspec = {[0.9 0.9 0.9]; [0.8 0.8 0.8]; [0.6 0.6 0.6]; ...
  [0.4 0.4 0.4]; [0.2 0.2 0.2]};
linespec = {'-', ':', '-.', '--'};
figure(1); cla;
hold on
for i = 1:20
  plot(x,y(:, i), 'Color', colorspec{mod(i,5)+1}, 'LineStyle', ...
    linespec{floor(i/5)+1})
end

[Ved]

Thanks a Lot, Simon.

But i am getting all 20 curves in different gray shades.

[Simon]

Hi!

Of course you have to define a usable colorspec. Take a look at http://en.wikipedia.org/wiki/RAL_colour_standard and follow the links there. There are many colors with their RGB values. Mind that matlab uses RGB values between 0 and 1, and not between 0 and 255!

[Kamilu Sanusi]

I would appreciate if you can help me with this problem. I have a system matrix A containing a damping variable D of which I want to see how it affects the position of eigenvalues on pzmap.

1. Please how do I link the eigen values of the same value of D together by a line?
2. How do i link only corresponding eigenvalue Lambda1 of different value oF D together, and the same thing applicable to other corresponding values of lampdas on the pz maz
3. with arrow showing possible direction of motion of eigenvalue as a result of change in D

Ta1 = 24; Ta2 = 27; Ta3= 20;

H11 = -0.0641; H12 = 0.0359;

H21 = 0.1176; H22 = -0.2057;

H31 = 0.2077; H32 = 0.1961;

for D = [0 7 10 15 20 25 40 70]

A = [0 0 1 0 -1;0 0 0 1 -1;(-H11/Ta1) (-H12/Ta1) (-D/Ta1) 0 0;...

(-H21/Ta2) (-H22/Ta2) 0 (-D/Ta2) 0;(-H31/Ta3) (-H32/Ta3) 0 0 (-D/Ta3)];

Eig = eig(A);

a = Eig(1,1);

b = Eig(2,1);

c = Eig(3,1);

d = Eig(4,1);

e = Eig(5,1);

s = tf('s');

T = (1)/((s-a)*(s-b)*(s-c)*(s-d)*(s-e));

P = pole(T);

if D == 7

pzmap(T)

end

hold on

if D == 15

pzmap(T)

end

hold on

if D == 25

pzmap(T)

end

end

[Kamilu Sanusi]

@Image Analyst, @CPS, @Kelly Kearney how do i make the marker thick on the pzmap please?

[Image Analyst]

@Kamilu Sanusi sorry I don't have that function on my computer. See if there is a 'LineWidth' or 'MarkerSize' option for it.

help pzmap

 PZMAP  Pole-zero map of dynamic systems.
 
    PZMAP(SYS) computes the poles and (transmission) zeros of the
    dynamic system SYS and plots them in the complex plane. The poles 
    are plotted as x's and the zeros are plotted as o's.  
 
    PZMAP(SYS1,SYS2,...) shows the poles and zeros of several systems
    SYS1,SYS2,... on a single plot. You can specify distinctive colors 
    for each model, for example:
       pzmap(sys1,'r',sys2,'y',sys3,'g')
 
    [P,Z] = PZMAP(SYS) returns the poles and zeros of the system in two 
    column vectors P and Z. No plot is drawn on the screen.  
 
    The functions SGRID or ZGRID can be used to plot lines of constant
    damping ratio and natural frequency in the s or z plane.
 
    For arrays SYS of dynamic systems, PZMAP plots the poles and zeros of
    each model in the array on the same diagram.
 
    See PZPLOT for additional graphical options for pole/zero plots.
 
    See also PZPLOT, POLE, ZERO, SGRID, ZGRID, RLOCUS, DYNAMICSYSTEM.

    Documentation for pzmap
       doc pzmap

    Other uses of pzmap

       DynamicSystem/pzmap    lti/pzmap

Answer 2

[Kelly Kearney]

Also, using colormaps and set with multiple handles + cell arrays can be helpful if you need a lot of colors.

 x = 1:100;
 ii = (1:20)';
 y = ii*log(x);

 h = plot(x,y);
 set(h, {'color'}, num2cell(jet(length(ii)), 2));

[Ved]

thanks a lot kelly !

[Sergey Kasyanov]

Thanks!

[Saksham Gakhar]

thank you!

Answer 3

[Image Analyst]

Simon showed you how to specify custom colors for each curve. If you want to know how to change the default color order, see my demo attached below.

[Ved]

thank you Image Analyst.

Answer 4

[Korosh Agha Mohammad Ghasemi]

%https://zil.ink/korosh                       -------- Ways to contact me ----------
% Korosh Agha Mohammad Ghasemi !
%  Chemical Engineering at Shiraz University
x=linspace(0,2,100);
figure;
for a=[0.1 0.5 1 2 4]
y=x.^a;     %The function is hypothetical
if a == 0.1    %Any color can be substituted
    y=x.^a;
    plot(x,y,'k')  %Now choose the color
    hold on
elseif a == 0.5
    y=x.^a;
    plot(x,y,'b')   %Now choose the color
    hold on
elseif  a==1
    y=x.^a;
    plot(x,y,'g')    %Now choose the color
    hold on
elseif a==2
    y=x.^a;
    plot(x,y,'r')   %Now choose the color
    hold on
elseif a==4
    y=x.^a;
    plot(x,y,'y')   %Now choose the color
hold on
grid on
end
end

Answer 5

[PeopleMATLAB]

colormap jet;
cmap=colormap;
for i=1:5
   Plot_color=cmap(i/5,:);   
   plot(x, y(i,:), 'Color', Plot_color);
   hold on;
end
hold off;

[K275]

FYI: This code generates an error because i/5 is not an integer or logical.

[C S]

just use i*5 and you are okay

Answer 6

[farhat khan]

gys i have a question ..... how to detect the object with color based detection if the required object have more then one color e.g green and black ..........

[Image Analyst]

I don't beleive you can plot a single set of data with two colors and one call to plot (plotyy notwithstanding). You have to keep track of the handle of the things you plotted:

hGreen = plot(x1, y1, 'g-'); % Plot a green line.
hBlack = plot(x2, y2, 'k-'); % Plot a black line.

I'm not sure how you'd detect what the color was if you didn't save the handle to the colored line you plotted, but maybe there is a way by using findobj() and seeing if you can get the color of any line object as a property. It's certainly not as straightforward so I recommend you just save the handles to the colors of the lines you drew, if you plan to detect them later.

Answer 7

[SYAHIRAH ZAKI]

hi does anoyne know how to get different plot colors for each of my graph?

if i change the 'r' to 'g', i only get one color for each of my graph. I need each of my plot in different colour. please help me :(

% Script file graph2.
% Several plots of the rational function y = x/(1+x^2)
% in the same window.
k = 0;
for n=1:3:10
 n10 = 10*n;
 x = linspace(-2,2,n10);
 y = x./(1+x.^2);
 k = k+1;
 subplot(2,2,k)
 plot(x,y,'r')
 title(sprintf('Graph %g. Plot based upon n = %g points.' ...
 , k, n10))
 xlabel('x')
 ylabel('y')
 axis([-2,2,-.8,.8])
 grid
 pause(3);
end

Answer 8

[Da Bu]

for a small set of colors, you can use ColorOrderIndex

t=1:0.1:2*pi;
for i=1:5
    plot(t,sin(t)*i), hold on
    ax = gca;
    ax.ColorOrderIndex = i;
end