Without this it will cause a nil dereference resulting in
Nasal runtime error: non-objects have no members
at D:/Program Files/FlightGear 2018.2.2/data/Nasal/canvas/map/WPT.lcontroller, line 57
called from: D:/Program Files/FlightGear 2018.2.2/data/Nasal/canvas/map/WPT.lcontroller, line 79
called from: D:/Program Files/FlightGear 2018.2.2/data/Nasal/canvas/MapStructure.nas, line 1088
called from: D:/Program Files/FlightGear 2018.2.2/data/Nasal/geo.nas, line 384
called from: D:/Program Files/FlightGear 2018.2.2/data/Nasal/canvas/MapStructure.nas, line 1051
called from: D:/Program Files/FlightGear 2018.2.2/data/Nasal/canvas/MapStructure.nas, line 1059
called from: D:/Program Files/FlightGear 2018.2.2/data/Nasal/canvas/map/WPT.lcontroller, line 26
called from: D:/Program Files/FlightGear 2018.2.2/data/Nasal/globals.nas, line 119