Why is my Watch Pro not accurately tracking distance/calories during outdoor workouts?

In outdoor exercise mode, the distance information is affected by GPS positioning information, and the calories burned are calculated based on the distance traveled.If the area you are exercising in is not open enough, for example, you go through an underground passage or pass by buildings, the GPS signal will be lost, causing statistical bias in your data. At the same time, if you do not stop or pause the exercise on your Watch Pro when you finish your workout, and you proceed to take public transportation, this will also cause a certain amount of error in your data.