title: Finding geohashes of certain length within radius from a point
body: <p>I have points with a given latlong and a distance around them - e.g. { 40.6826048,-74.0288632 : 20 miles, 51.5007825,-0.1258957 : 100 miles}. If I pick a fixed geohash length (say equals to ~ 1x1mile) how can I find all the geohash entries of that length that are with the given radius from each point? </p>
  
  <p>To add some background - the reason I want to do that is so I can save a cache keyed by the geohash id with a value of the list of points for which the given geohash is within radius (and also matches some custom eligibility rules). Then I can do a quick lookup for a user's location geohash to find all the eligible points around them.</p>