I have a plot which is having some points. How to join those points

I have a plot which is having some points. How to join those points

[Image Analyst]

How did you put those points on the graph in the first place. The Mind Reading Toolbox has not been released yet so we'd need to see your code.

[Walter Roberson]

How they were put on the graph in the first place does not matter overly: it is possible to search all the different kinds of graphics primitives looking for the points. You do not need the Mind Reading Toolbox until you try to decide what order to connect them in.

Answer 1

[Walter Roberson]

That gets a bit involved if you are using R2014a or earlier and using scatter() (but certainly can be done). It gets notably messier to work out if you are using patch() to draw the points, or one of the routines that invokes patch such as some of the contour variants. If you are using a surface or mesh plot in which some of the points are black (or more properly, the same color as the background they are plotted on) then you could get into arguments about whether those visually-hidden points should be drawn or not.

There are ways it can be done. But really the way it should be done is to keep track of the points at the time you would normally plot them, and plot the joining line once you know them all. For example, instead of

   for K = 1 : 20
     %generate one point
     x = K.^2;
     y = sin(x);
     %plot the one point
     plot(x, y); 
     hold on
   end

You would use

   %generate all of the points
   for K = 1 : 20
     x(K) = K.^2;
     y(K) = sin(x(K));
   end
   %plot all of the points
   plot(x, y);