Can anyone please explain the syntax and purpose of plot() function?

I need to know if I can plot some (x,y) coordinate points on a .png file, for this purpose I need to know the proper syntax and usage of plot().

[dpb]

All the syntax of plot is given at

doc plot

I have no idea what you mean when you say ...plot some (x,y) coordinate points on a .png file...

Explain precisely what you want as an end result; attaching a sample plot would likely be even better.

[fawad khan]

The end result should be 25 points plotted on an image file.

[dpb]

How do you plot on a file is the question?

If you really mean on a displayed image, then as the other respondent answered, you've simply got to scale to the image coordinates what it is that you wish to plot and have at it...

[fawad khan]

Okay, thanks a lot.

Answer 1

[Chad Greene]

If you're trying to plot x,y data on an image, you can do this:

imshow('coins.png')
hold on
plot(1:300,linspace(1,20,300).^2)

where units plotted by plot are in pixels. Or your x,y data have some units other than pixels, you'll have to figure out the right arrays of xdata and ydata corresponding to pixels in the image. Then you can specify 'xdata',xarray,'ydata',yarray when you call imshow.