Draw lines between points in Matlab

Question

I have a text file ("coordinates.txt") that contains x and y coordinates of points. File looks like this:

11 44 2 9

11 44 5 8

2 1 6 11

2 1 10 3

I need to draw lines between (11, 44) to (2, 9), (11, 44) to (5, 8), (2, 1) to (6, 11), and (2, 1) to (10, 3).

I can do this by manually like:

x = [11 11 2 1; 2, 5, 6, 10];

y = [44 44 1 1; 9 8 11 3];

plot (x, y).

But the actual file is quite long and I need to "automate" this process.

I tried:

load coordinates.txt;

edit coordinates.txt;

x1= [coordinates(:, 1); coordinates(:, 3)];

y1 = [coordinates(:, 2); coordinates(:, 4)];

plot (x1, y1).

It gives me lines drawn from (11, 44) to (2, 9), (2, 9) to (5, 8), (5, 8) to (6, 11), (6, 11) to (10, 3).

Could anyone help?

Answer 1

Assuming you read the file correctly to an n-by-4 matrix coordinates.
To plot

plot( coordinates(:,[1 3]).', coordinates(:,[2 4]).' );

should do the trick