title: Clustering Algorithms for a Set of Data Points
body: <p>I have a collection of Points objects, containing latitude and longitude (along with a few other irrelevant properties). I want to form clusters i.e. collections of points that are close together, relative to other points. </p>
  
  <p>Alternatively, I would like an algorithm which, if given a list of clusters containing close-by points and a new point, determines which cluster the new point belongs to (and adds it to a new cluster if it doesn't belong to an existing cluster).</p>
  
  <p>I looked at Hierarchical Clustering algorithms but those run too slow. The k-means algorithm requires you to know the number of clusters beforehand, whcih is not really very helpful.</p>
  
  <p>Thanks!</p>