Find if lines intersect
18 views (last 30 days)
Show older comments
I have a matrix containing data for points on a vector v = [x;y]. let's say:
%
M = [v1_x1 v1_x2 v1_y1 v1_y2; v2_x1 v2_x2 v2_y1 v2_y2; v3_x1 v3_x2 v3_y1 v3_y2]
Where v1_x1 and v1_y1 are points of a the vector v1. v1_x2 and v1_y2 are the coördinates of the other point of the vector v1. For every vector there are two points known.
Now I want to find if any of those vectors intersect.
there is an intersection point when:
det(v1-v3,v2-v3)*det(v1-v4,v2-v4) < 0
or
det(v3-v1,v4-v1)*det(v3-v2,v4-v2) < 0
Where v1 = [x1;y1]
How can I implement this in a code
7 Comments
Walter Roberson
on 20 Sep 2017
Roger Stafford has posted the code to determine intersection of line segments. It was probably about 16 months ago. I am on my phone so I cannot easily search for the post
Richard
on 19 Apr 2019
I am unable to locate any code by Roger Stafford to determine line intersection. Based on other web searching, I believe the code might include a sweeping algorithm for intersection of 3D line segments. Can anyone help here?
Answers (1)
Jan
on 20 Sep 2017
You find the method using determinants e.g. here: https://www.mathworks.com/matlabcentral/fileexchange/35606-line-line-intersection--2d-
But perhaps you do not mean the lines through the 2 points, but only the section from one point to the other.
2 Comments
Jan
on 21 Sep 2017
intersect compares the elements of the input vectors. This is not the intersection of the lines. You did not explain until now, if you mean the lines limited by the points, or the lines with infinite length through these points.
See Also
Categories
Find more on Historical Contests in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!