title: What does ValueError mean?
body: <p>I,m trying to calculate the shortest distance between a collection of points and a line segment. Everything goes well untill it has to calculate the distance using values from two sets of arrays one for the x distances and one for the y distances. </p>
  
  <p>The line for calculating the distance is:</p>
  
  <pre><code>d = np.sqrt( dx**2 + dy**2 ).
  </code></pre>
  
  <p>It tells me that::</p>
  
  <pre><code>ValueError: operands could not be broadcast together with shapes (3312,) (0,) 
  </code></pre>
  
  <p>I've used the script before with another set of values and it works perfectly. But now it does not any more. And I tried tot find the meaning of the error message but have not been successful so far. Can someone help?</p>