how to name points in a plot?

Hello,

i am interested in naming points of my plot wiht numbers. So i tried it the following way where i is the number that should describe my node.

for i=1:length(xk)

    plot(xk(i),yk(i),sprintf( '#%i'))

    i=i+1;

    hold on
end

but it didnt work and this error occured:

--->??? Error using ==> plot

--->Error in color/linetype argument

--->Error in ==> Plotten at 51

---> plot(xk(i),yk(i),sprintf( '#%i'))

can anyone help me with that please?

with best regards, John

Answer 1

[Stephan M. H.]

Hi John,

where you used sprint, the plot function expects as input LineSpec or 'PropertyName' followed by Propertyvalue.

I guess a direct way would be using the text function

    ...
    plot(xk(i),yk(i))
    text(xk(i),yk(i),num2str(i))

best,

Stephan

[John]

Thx for your answers!.... trying so, i have the following code:

    for i=1:2:length(xk)
    plot(xk(i:(i+1)),yk(i:(i+1)),'r-','LineWidth' ,1)
    xk(i:(i+1));
    yk(i:(i+1));
    i=i+2;
    hold on
    end

    for i=1:length(xk)
    plot(xk(i),yk(i))
    text(xk(i),yk(i),num2str(i))
    i=i+1;
    hold on;
    end

There remains the problem that the node´s numbers are somehow overwritten various times, i cannot explain that because i placed the text command after the line plots as you can see.

best greetz, John

[Azzi Abdelmalek]

What i=i+1 is doing in your code?

[John]

thx i found the mistake...the irritation was due to strange loops^^

it works well now and the numbers arent overwritten anymore.

Answer 2

[Azzi Abdelmalek]

for i=1:length(xk)
  text(xk(i),yk(i),num2str(i))
  hold on
end

[Sushree Patra]

Without for loop how to provide the numbering to each point.

Means if

x1= 167*rand (50,1);
y1=302* rand (50,1);
plot(x1,y1,'b*');