anchor.diff:      DeltaLat = MaxLat - MinLat,
       DeltaLon = MaxLon - MinLon,
       Bits = geohash_bits(DeltaLat, DeltaLon, 63),
  -    max(trunc(Bits/5), 0).
  +    max(trunc(Bits/5), 1).
   
   %% @doc Determine the bounding box of coordinates for a point and radius
   %% distance on the earth.
  
positive.code: -spec nearby(float(), float(), float()) -> [binary()].
  nearby(Lat, Lon, Rad) ->
      Precision = nearby_precision(Lat, Lon, Rad),
      error_logger:info_msg("encoding ~p,~p with precision ~p~n", [Lat, Lon, Precision]),
      {ok, GeoHash} = encode(Lat, Lon, Precision),
      expand(GeoHash).
  
  
negative.code: %% @doc Calculate 8 neighboring geohashes
  -spec neighbors(binary()) -> [binary()].
  neighbors(C) ->
      {ok, N} = neighbor(C, n),
      {ok, W} = neighbor(C, w),
      {ok, S} = neighbor(C, s),
  