MATLAB Answers

Paul
1

How to draw a square with specific plot points

Asked by Paul
on 8 Oct 2013
Latest activity Answered by Camilo Malagon Nieto on 8 May 2019
I'm trying to create two squares, one larger one, and the other within it.
I attempted to create one using matrices. I create one with x = [0 0 1 1] and y = [0 1 1 0]
I wanted a line to connect each one of the points, to thus create a line. However, when I did that, I only received three lines connect between the dots for some reason. The bottom points (0,0) and (1,0) for some reason were not connected. I then attempted to make a second square, and the same thing happened, with the two lower points in regards to their Y points did not connect. I tried using the rectangle function as well, but can't get a square within a square to appear. Any help would be great. Thanks

  1 Comment

Please write this code x = [0 0 1 1 0]; y = [0 1 1 0 0]; plot(x,y,'r', 'LineWidth',3)

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2 Answers

Answer by Image Analyst
on 8 Oct 2013
Edited by Image Analyst
on 8 Oct 2013
 Accepted Answer

You need 5 points - the last one is to "close off" the square, otherwise it won't be closed because you didn't draw the line back to the starting point. So, try this
x1=0;
x2=1;
y1=0;
y2=1;
x = [x1, x2, x2, x1, x1];
y = [y1, y1, y2, y2, y1];
plot(x, y, 'b-', 'LineWidth', 3);
hold on;
x1=0.25;
x2=.75;
y1=0.25;
y2=.75;
x = [x1, x2, x2, x1, x1];
y = [y1, y1, y2, y2, y1];
plot(x, y, 'b-');
xlim([-1, 2]);
ylim([-1, 2]);

  2 Comments

perfect!
If you ever had to create two similar objects like this (for example two squares), would you recommend going about it another way? I tried with the rectangle function as well, it seemed potentially more convenient.
Once again, thanks for the response.
I think the way I did it is easier to understand than rectangle. In my mind I just visualize starting at the upper left corner and marching around the square in a clockwise fashion. First I do the x's then I do the y's. And so it's really quick for me to construct the 5 element x and y matrices.

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Answer by Camilo Malagon Nieto on 8 May 2019

Worth to say that there is a function now to make a rectangle and smooth the corners.
Cheers,

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