I have been adding GPS logging to my Bicycle Dashcam. All of the example Python code (eg: https://gpsd.gitlab.io/gpsd/gpsd-client-example-code.html) I’ve found online throws this error after about a minute:
Exception has occurred: KeyError
File "example2.py", line 12, in
while 0 == session.read():
I’m not sure if this is a problem unique to my GPS receiver, but it regularly sends data that is not “class”:”TPV” (eg: “class”:”SKY”) – TPV is the data with coordinates, and whenever that happens, all the sample code throws a KeyError.
I’ve found the easiest way to fix this is to add a TRY/EXCEPT inside the forever loop, catch the KeyError expection, and PASS. Here is an adaptation of code I found on Stackoverflow that solves the problem – I’ve submitted it as an improvement, hopefully they accept my edits!
import threading import time from gps import * from datetime import datetime class GpsPoller(threading.Thread): def __init__(self): threading.Thread.__init__(self) self.session = gps(mode=WATCH_ENABLE) self.current_value = None def get_current_value(self): return self.current_value def run(self): while True: #moved the try INTO the forever loop, so pass from the except resumes collecting data try: self.current_value = self.session.next() time.sleep(0.2) # tune this, you might not get values that quickly except KeyError as e: #catch the KerError, and return to the forever loop pass except StopIteration: pass #if __name__ == '__main__': gpsp = GpsPoller() gpsp.start() # gpsp now polls every .2 seconds for new data, storing it in self.current_value while 1: # In the main thread, every 5 seconds print the current value time.sleep(5) value=gpsp.get_current_value() print(value)
Update (May 6, 2023): I found a better solution: the gpsd-py3 library works great.