//first time you build the map you add all the car and roads near you public UserMap(Vehicle vehicle, IDataServer dataServer) { _currentVechicle = vehicle; _dataServer = dataServer; CurrentCarGpsLocation = _currentVechicle.CurrentLocation; try { Roads = _dataServer.GetRoadsAroundLocation(CurrentCarGpsLocation); } catch (Exception) { //should add here logger/error handling throw; } try { Vechicles = _dataServer.GetVechicalesAroundLocation(CurrentCarGpsLocation); } catch (Exception) { //should add here logger/error handling throw; } }