anchor.diff:      end, RStar).
   
   %%
  -
  --define(PI, 3.141592653589793).
   
   %% @doc Converts degrees to radians.
   
  
positive.code:     distance/4
  ]).
  
  -ifdef(NIFEXT).
  
  -on_load(init/0).
  
negative.code: 
  -spec inbetween(number(), number(), number(), number(), erstar:rtree()) -> [erstar:treeleaf()].
  
  inbetween(Phi, Lambda, FartherThan, CloserThan, RStar) when FartherThan > ?PI / 2.0, Lambda > 0.0 ->
      inbetween(-Phi, Lambda - ?PI, ?PI - CloserThan, ?PI - FartherThan, RStar);
  
  inbetween(Phi, Lambda, FartherThan, CloserThan, RStar) when FartherThan > ?PI / 2.0 ->
      inbetween(-Phi, Lambda + ?PI, ?PI - CloserThan, ?PI - FartherThan, RStar);
  
  inbetween(Phi, Lambda, FartherThan, CloserThan, RStar) ->
      Extents = small_circle_extents(Phi, Lambda, CloserThan),
      erstar:walk(fun (Type, Bound) ->
  