title: Find all nearest neighbors within a specific distance
body: <p>I have a large list of x and y coordinates, stored in an <code>numpy</code> array. </p>
  
  <pre><code>Coordinates = [[ 60037633 289492298]
   [ 60782468 289401668]
   [ 60057234 289419794]]
  ...
  ...
  </code></pre>
  
  <p>What I want is to find all nearest neighbors within a specific distance (lets say 3 meters) and store the result so that I later can do some further analysis on the result.</p>
  
  <p>For most packages I found it is necessary to decided how many NNs should be found but I just want all within the set distance.</p>
  
  <p>How can I achieve something like that and what is the fastest and best way to achieve something like that for a large dataset (some million points)?</p>