title: Collision Detection for a Matplotlib graph within Python
body: <p>I've been creating a physics projectile simulation for my computer science project, and one of the key elements of it is collision detection. Essentially, I need the program to flag up when the "projectile" has hit a certain point.</p>
  
  <p>As an example, if I were to plot a simple line graph like<br>
  ax1.plot([0,1,2,3,4,5],[5,4,3,2,1])<br>
  What sort of function would be able to determine if the line produced by the graph passes through the point (3.5,1.5)?</p>
  
  <p>Currently, the code is simply determining the distance travelled by the projectile in the x and y direction each second, so I don't believe a form of estimation can be used, though I may be wrong.</p>
  
  <p>Thank you in advance</p>