Solved

Determine if two points are on the same side of a line

Posted on 2014-03-01
3
483 Views
Last Modified: 2014-03-01
I have two points representing a line:
33.792262, -84.305002
33.739889, -84.289553
I also have two points A and B:
A
33.748739, -84.354355
B
33.767649, -84.273760
What I need is a javascript function that will give true/false return if both points are on the same side of the line. If any or both points are on the line then it should return true.
I found this http://j.mp/1of7JUe solution but I need it written as javascript function and I myself don't know javascript programming.

Thank you.
0
Comment
Question by:pplb
  • 2
3 Comments
 
LVL 28

Accepted Solution

by:
Pravin Asar earned 500 total points
ID: 39898129
<script type="text/javascript">
          function Point2D (x,y) {
                this.x = x;
                this.y = y;
                return this;
          };
          
          function Vector2D(p1,p2) {
                this.x = p2.x-p1.x;
                this.y = p2.y-p1.y;
                return this;
          };
          
          function VectorMath() {
                this.dotProduct =function (v1,v2) { var dot= v1.x*v2.x+ v1.y*v2.y; return dot; };
                this.normalVector = function (v1) { t=v1.x; v1.x=v1.y; v1.y=-t; return v1; };
          };
          
          // Define Points
          p1 = new Point2D(33.792262, -84.305002);
          p2 = new Point2D(33.739889, -84.289553);
          p3 = new Point2D(33.748739, -84.354355);
          p4 = new Point2D(33.767649, -84.273760);
          // Define Vector for Base line
          v1 = new Vector2D(p1,p2);
            // Get Normal Vector
          v1 = (new VectorMath()).normalVector(v1);
            // Define Vector 1st Point to check
          v2 = new Vector2D(p1,p3);
            // Define Vector 1st Point to check
          v3 = new Vector2D(p1,p4);
          dot1 = (new VectorMath()).dotProduct (v1,v2);
          // Can you get normalized value
          dot1 = dot1 /Math.abs(dot1);
          dot2 = (new VectorMath()).dotProduct (v1,v3);
          // Can you get normalized value
            dot2 = dot2 /Math.abs(dot2);
            // Same Sign (Points on Same side) or different sign (Points on different side)
          if (dot1 == dot2) { alert ('Points on Same Side');} else { alert ('Points are not on same side');}
    </script>
0
 
LVL 28

Expert Comment

by:Pravin Asar
ID: 39898130
You may look at

http://sylvester.jcoglan.com/docs.html

This is a good library.
0
 

Author Closing Comment

by:pplb
ID: 39898176
Thank you.
0

Featured Post

Highfive + Dolby Voice = No More Audio Complaints!

Poor audio quality is one of the top reasons people don’t use video conferencing. Get the crispest, clearest audio powered by Dolby Voice in every meeting. Highfive and Dolby Voice deliver the best video conferencing and audio experience for every meeting and every room.

Join & Write a Comment

What is a Lightbox? A Lightbox is the effect you see when you click, for example, an image and the screen fades out and up pops the same image but in its full size dimensions. There are lots of Lightbox effects for jQuery. Problem is they are a…
Introduction If you're like most people, you have occasionally made a typographical error when you're entering information into an online form.  And to your consternation, the browser remembers the error, and offers to autocomplete your future entr…
The viewer will learn how to dynamically set the form action using jQuery.
The viewer will learn the basics of jQuery, including how to invoke it on a web page. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery.: (CODE)

760 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

17 Experts available now in Live!

Get 1:1 Help Now