fix crash when no position

Jxck-S/plane-notify#117

calculate_headings.py

@@ -17,6 +17,9 @@ def calculate_cardinal(d):
     card = dirs[ix % len(dirs)]
     return card
 def calculate_deg_change(new_heading, original_heading):
+    if new_heading is None:
+        print("Track heading missing. No change")
+        return 0
     """Calculates change between two headings, returns negative degree if change is left, positive if right"""
     normal = abs(original_heading-new_heading)
     across_inital = 360 - abs(original_heading-new_heading)

planeClass.py

@@ -618,7 +618,8 @@ class Plane:
                     from calculate_headings import calculate_deg_change
                     track_change = calculate_deg_change(self.track, self.last_track)
                     track_change = round(track_change, 3)
-                    self.circle_history["traces"].append((time.time(), self.latitude, self.longitude, track_change))
+                    if self.latitude is not None and self.longitude is not None:
+                        self.circle_history["traces"].append((time.time(), self.latitude, self.longitude, track_change))
 
                 total_change = 0
                 coords = []