title: Plotting points in a semi-circle
body: <p>I am trying to plot points, evenly spaced in a semi-circle, using JavaScript.</p>
  
  <p>So far, I have worked out the formula for calculating the Y co-ordinate based on the X co-ordinates, which produces a semi-circle. The problem is, because my X co-ordinates are at regular intervals, the points appear closer together at the apex, and more spaced out at either ends of the arc, (in a sort of parabolic configuration). What I want to produce is evenly spaced points, like the minutes on a clock face.</p>
  
  <p>Here is my code so far:</p>
  
  <pre><code>$radius = 200;
  for ($i = -10; $i &lt;= 10; $i++) {
      $pos_x = $i * 20;
      $pos_y = Math.round( Math.sqrt( Math.pow($radius,2) - Math.pow($pos_x,2) ) + $radius );
  }
  </code></pre>
  
  <p>See my JSfiddle for a visual example: <a href="https://jsfiddle.net/7Lbqhtme/2/" rel="nofollow">https://jsfiddle.net/7Lbqhtme/2/</a></p>
  
  <p>I think all that I need to change is a multiplier on $pos_x so that the intervals decrease the further from 0 you get, (but I only have GCSE Maths and am struggling with this)...</p>
  
  <p>Can someone please help me adjust this code, so that the output points are more uniformly placed?</p>
  
  <p>PS. It doesn't have to be entirely accurate, (using SIN and COS, etc), it can just be a multiplier which decreases the $x interval the further from 0, so that the points appears more evenly spaced.</p>
  
  <p>Thanks for looking!</p>