Originally Posted by
njkayaker
...if the sampling rate is too low, would it result in a large difference in distance?
If the sampling rate is too low, the Nyquist frequency will tell you how large the distance error ought to be. Reduced sampling is like running a low pass filter on the data: it filters out the high frequency bits.
For anything I've used, an iPhone or a Garmin, the sampling rate doesn't appear to be too low.
So since your sampling rate is not too low, are you still seeing errors in distance calculations? That would suggest some other type of error.