HI All,
How can I calculate direction vector of a line segment, defined by start point (x1, y1) and end point (x2, y2)?
Cheers.
+5
A:
(x2 - x1, y2 - y1)
If you want the unit direction vector, divide each component by sqrt((x2 - x1)² + (y2 - y1)²).
Mark Byers
2009-11-23 23:48:55
Might want to add something about normalizing.
GMan
2009-11-23 23:49:31
Do I have to do something to deal with -ve and +ve coordinates???
Zinx
2009-11-23 23:51:44
No, it works for negative coordinates too.
Mark Byers
2009-11-23 23:54:15
cool, thanx for help. Cheer
Zinx
2009-11-23 23:55:35
+2
A:
Hi
The direction vector can be represented as (x2 - x1)i + (y2 - y1)j where i and j are unit vectors along x and y axis respectively.
cheers
Andriyev
2009-11-23 23:50:34
+2
A:
If you want the vector from the end of vector (x1,y1) to the end of vector (x2,y2), the answer is
(x2-x1, y2-y1) + (x1,y1)
If you want the (unit-length) direction vector, then the answer is
((x2-x1)/L, (y2-y1)/L)
where L=√((x2-x1)² + (y2-y1)²) (thats $L=\sqrt{(x2-x1)^2 + (y2-y1)^2}$ in LaTeX).
Barry Wark
2009-11-23 23:53:00
@Zinx, Yes a * (x,y) is multiplying a vector by a scalar, which corresponds to dividing each component of the vector by a.
Barry Wark
2009-11-23 23:57:11