UAS Flight Operations Levels
     In the Roadmap for the Application and Technology Development of UAVs in Japan (28th Apr. 2016 The 
       Public-Private Sector Conference on Improving the Environment for UAVs), four levels of UAS flight 
       operations were defined as shown below.
             Populated
               Areas                                                   Level 4
         (including urban areas)                             BVLOS Flight over populated areas  
                                                             (including urban areas)
                               Level 1         Level 2
           Less-Populated       VLOS
               Areas           (Remotely         VLOS                  Level 3
         （remote islands,       Piloted)
         mountainous areas, etc.)                            BVLOS Flight over less-populated areas 
                                                             (remote islands, mountainous areas, etc.)
                                  Visual Line of Sight         Beyond Visual Line of Sight
                                       (VLOS)                         (BVLOS)
   Roadmap for the Application and Technology Development of UAVs in Japan (28th Apr. 2016 The Public-Private Sector Conference on Improving the Environment for UAVs)
         http://www.kantei.go.jp/jp/singi/kogatamujinki/pdf/shiryou6.pdf