I exactly can't understand what is your problem, please describe more.

Do you want plot each point in particular color that defined by 3th vector?

%use this code

%if your vector was x,y&z

np=length(x);

clr=colormap(jet(np));

hold on;

for i=1:np;

plot( x(i), y(i), '.', 'color', clr(z(i),:) );

end;

thanks Hamid for the answer....actually I am working with a spectra..there are therefore thousands of points..i want these points to be defined by a colour code (suppose blue, yellow and red) which will be defined by the 3rd vector....e.g.lowest 3rd vector vaue will give darkest blue colour, middle value will be completely yellow and highest value will be red...other points in between them will vary between these colors with gradual changes from blue to yellow and yellow to red.......another thing i wanted to mention is that i am completely new in matlab....i practically know nothing of it...so help me accordingly

After I ran your script it's showing:

"??? Subscript indices must either be real positive integers or logicals."

%I understand these & I attach my MATLAB code:

%or copy this script into a blank m-file and run (F5) it.

%this script plot x,y,z vectors (x&y are coordinate) in 2D axis and fit 3rd

%term (or z) to a colorbar that we created.

clc

clear

%% initilizing

x=1:0.1:20;%your X vector

y=sin(x);%your Y vector

z=sin(1*x-0);%your Z vector

n=10;%number of colors from blue to yelow OR from yelow to red

%% creat color vector

k=2*n-1;%number of all colors

i=1:n;

clrX=(i-1)/(n-1);

%red vector

clr(1:n,1)=clrX;

clr(n:end,1)=1;

%green vector

clr(1:n,2)=clrX;

clr(n:end,2)=1-clrX;

%blue vector

clr(1:n,3)=1-clrX;

clr(n:end,3)=0;

%% fitting color vector to z vector

Gain=(max(z)-min(z))/(k-1);

clrIndx=round((z-min(z))/Gain)+1;

%% plot points and fitting colorbar to the z vector

figure;

hold on;

for i=1:length(x)

plot(x(i),y(i),'marker','*','color',clr(clrIndx(i),:));

end

%I hope this code be benefit for you

clr(1:n,2)=clrX;

clr(n:end,2)=1-clrX;

After I am giving this command it's showing: "Subscripted assignment dimension mismatch."

What to do?

Moreover I ran your .M file it's only adding colour to the points...I need a line plot with gradual change in colours

%Change in colours depended on N value, e.g. if you set n=3; you have k=2n-1=5 %colour classify in your Z vector. for line plot use this code:

%this script plot x,y,z vectors (x&y are coordinate) in 2D axis and fit 3rd

%term (or z) to a colorbar that we created.

clc

clear

%% initilizing

x=1:0.1:20;%your X vector

y=sin(x);%your Y vector

z=sin(2*x-1);%your Z vector

n=5;%number of colors from blue to yelow OR from yelow to red

%% creat color vector

k=2*n-1;%number of all colors

clr=ones(k,3);

i=1:n;

clrX=(i-1)/(n-1);

%red vector

clr(1:n,1)=clrX;

clr(n:end,1)=1;

%green vector

clr(1:n,2)=clrX;

clr(n:end,2)=1-clrX;

%blue vector

clr(1:n,3)=1-clrX;

clr(n:end,3)=0;

%% fitting color vector to z vector

Gain=(max(z)-min(z))/(k-1);

clrIndx=round((z-min(z))/Gain)+1;

%% plot points and fitting colorbar to the z vector

figure;

hold on;

for i=1:(length(x)-1)

plot(x(i:(i+1)),y(i:(i+1)),'color',clr(clrIndx(i),:));

end

I use MATLAB 2011a

thanks a lot Hamid...it's working perfectly fine now..

facing another problem...I think the colour bar is not integrated...when i am trying to include the colour bar..the bar is showing different colour ranges from the plot...please help

this colorbar that you uses,yourself creat it and it is difrent from Default colorbar of figure.

added this code to end of your script:

colormap(clr);

colorbar('yticklabel',num2str(([NaN,min(z):Gain:max(z)])'));

or use attached m-file

Thanks...But I wanted a gradual change of colours similar to the default colorbar...nways..this will do for the time being

If you give your mail id I will send an image...I want similar kind of result

You can attach any file here.

For gradual change of colors you must increase ''n'' value.

Check this

According to what I said

you must increase "n" value (e.g. n=50) then you see a gradual color bar.

are you work with spectrum?

what's your spectrometer?

I am working with NMR....I have increased the n value to 50 but I am not satisfied with the colour of the line plot...so when I tried to change it by changing the colour bar, it didn't work.....

simply use contour or contourf. If you have coordinates (x,y) and a function z(x,y) then you can use contour for representation. colorbar will be assigned automatically and you can change it by using it's property in figure tools

Thanks Azizi...Can you please write the script...I am completely new in MATLAB

You must say what is the arrangement of your data file.

What do you mean by arrangement? I have three variables:x,y and z..Each of them have815 values. There will be x vs y 2D plot which will have a gradual change of colour determined by 'z'

Here a matlab example, set the (x,y,c) data to whatever your (x,y,z) are, set the linewidth to what you juge being cute and then you will have to play with some extra parameters for the axes.

xdata = 1:100;

ydata = sin(xdata*pi/10);

cdata = cos(xdata*pi*pi/10);

p = patch([ xdata xdata(end:-1:1) ],...

[ydata ydata(end:-1:1)],...

[cdata cdata(end:-1:1)],...

'Marker', 'none', 'FaceColor','none')

set(gcf,'Renderer','zbuffer')

set(p,'EdgeColor','interp','LineWidth',5)

Oh! I forgot, you will have to play with the colormap to set the colors you want since the color vector is in fact an index vector to the colormap.

Thanks Francois...this is what I exactly wanted....thanks again

Also thanks to all for your help