title: Associate facebook user check-ins to list of cities based on latitude and longitude
body: <p>I am studying the development of an application that would show a user which cities in the world their friends have traveled to. To do this, I was thinking of getting a list of check-ins for each of the user's friends and mapping those check-ins to my list of cities based on each check-in latitude and longitude.
  This looks like the only way to achieve this since the Facebook graph API doesn't return a city locationId that I could use to map the check-in city to my own city list.</p>
  
  <p>I have absolutely no idea how to perform this mapping from a check-in lat/long to the lat/long I have stored for each city in my city table.
  Could anyone point me in the right direction or toward a tutorial explaining how this can be done?</p>
  
  <p>I only have a single pair of lat/long coordinates, so I suppose I would need to define for each city a range of latitudes and longitudes around the city center lat/long that would qualify a check-in for being deemed to take place in any given city, and then do a SQL query against my city table to find which city any given check-in finds itself in?
  Or is there another / better way of doing this?
  Thanks in advance for any tip and suggestion.</p>
  
  <p>Lothaire</p>