anchor.diff:  merge_mbr(Mbr1, Mbr2) ->
       {W1, S1, E1, N1} = Mbr1,
       {W2, S2, E2, N2} = Mbr2,
  -    {min(W1, W2), min(S1, S2), max(E1, E2), max(N1, N2)}.
  +    {erlang:min(W1, W2), erlang:min(S1, S2),
  +     erlang:max(E1, E2), erlang:max(N1, N2)}.
   
   
   find_area_min_nth([H|T]) ->
  
positive.code:     MbrE = calc_nodes_mbr(PartE),
      MbrS = calc_nodes_mbr(PartS),
      MbrN = calc_nodes_mbr(PartN),
      MaxWE = max(length(PartW), length(PartE)),
      MaxSN = max(length(PartS), length(PartN)),
      if
          MaxWE < MaxSN ->
              [{MbrW, PartW}, {MbrE, PartE}];
  
negative.code:         not IsDisjoint ->
              {W1, S1, E1, N1} = Mbr1,
              {W2, S2, E2, N2} = Mbr2,
              {erlang:max(W1, W2), erlang:max(S1, S2),
               erlang:min(E1, E2), erlang:min(N1, N2)};
          true ->
              {0, 0, 0, 0}
      end.
  