title: Google App Engine Geohashing
body: <p>I am writing a web application using GWT and App Engine.  My application will need to post and query items based on their latitude, longitude.</p>
  
  <p>As a result of google's distributed database design you can't simple query a set of inequalities.  Instead they suggest doing geohashing.  The method is described on this page.  </p>
  
  <p><a href="http://code.google.com/appengine/articles/geosearch.html" rel="noreferrer">http://code.google.com/appengine/articles/geosearch.html</a></p>
  
  <p>Essentially you pre compute a bounding box so that you can query items that have been tagged with that bounding box.</p>
  
  <p>There is one part of the process that I don't understand.  What does the "slice" attribute mean?</p>
  
  <p>Thanks for your help!</p>