The first argument is the filename of the GeoIPCity.dat file load_option = :standard, :index, or :memory. default :memory check_cache = true or false. default false

filesystem: read database from filesystem, uses least memory.

index: the most frequently accessed index portion of the database,

  resulting in faster lookups than :filesystem, but less memory usage than
  :memory.

memory: load database into memory, faster performance but uses more

  memory.

Pass this function an IP address as a string, it will return a hash containing all the information that the database knows about the IP

   db.look_up('24.24.24.24')
   => {:city=>"Ithaca", :latitude=>42.4277992248535,
       :country_code=>"US", :longitude=>-76.4981994628906,
       :country_code3=>"USA", :dma_code=>555,
       :country_name=>"United States", :area_code=>607,
       :region=>"NY"}