-record(monitor, {stations, measurements}).
-record(measurement, {date, type, value}).
-record(station, {name, coords}).

createMonitor() ->
  #monitor{stations = #{}, measurements = #{}}.

addStation(Monitor, Name, Coords) ->
  {monitor, Stations, Measurements} = Monitor,
  Station = #station{name = Name, coords = Coords},
  maps:put(Name, Station, Stations),
  maps:put(Coords, Station, Stations),
  maps:put(Station, [], Measurements),
  {monitor, Stations, Measurements}.


z takim dodawaniem też nie działa :( :
 Stations#{Name => Station, Coords => Station},
  Measurements#{Station => []},