anchor.diff:            ai => ai.tile.openstreetmap.org.
             al => al.tile.openstreetmap.org.
             am => am.tile.openstreetmap.org.
  -          an => an.tile.openstreetmap.org.
             ao => ao.tile.openstreetmap.org.
             ap => ap.tile.openstreetmap.org.
             aq => aq.tile.openstreetmap.org.
  
positive.code:           NA => {
              AG => [ag]
              AI => [ai]
              AN => [an]
              AW => [aw]
              BB => [bb]
              BL => [bl]
  
negative.code:           fm => fm.tile.openstreetmap.org.
            fo => fo.tile.openstreetmap.org.
            fr => fr.tile.openstreetmap.org.
            ga => ga.tile.openstreetmap.org.
            gb => gb.tile.openstreetmap.org.
            gd => gd.tile.openstreetmap.org.
  