This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

GPS Accuracy and Splits in Garmin Connect

Hi All,

I have a small gripe about the way the time is reported in Garmin Connect.
My watch is a Garmin Forerunner 305.

I went to the track and I ran 400m laps, in Lane 1. I kept as close as possible to the inside of the track (to ensure I get 400m readings on my watch).

So I look at my watch, at the end of each lap, the watch reads 405-408m. Fair enough.

I check the GPS accuracy at the point of time, it says 6-8m. Fair enough.

Now when I upload to Garmin Connect. It lists the distance of each lap as 0.41m. If I run for like, 4 laps, I would get 4 laps of 0.41m in Garmin Connect.

However the summary at the end for the 4 laps would say something like 1.63km (and not 0.41 * 4 = 1.64km).

Is there any way to increase the number of decimal places displayed, or at least ensure the summed numbers match?

0 Comage over 15 years ago

Does anybody have an answer from the GC team?

0 Comage over 14 years ago

Anybody knows?

0 BBECKER39 over 14 years ago

I don't think there is any reasonable way to ensure the summed numbers match.

Long answer:
The precision could probably be increased, but this would not ensure the summed numbers match. When rounding floating point numbers, this type of mismatch can always occur.

For example, if there are two laps which are each rounded to 0.41 km, the actual distance may be 0.406 km. These will then add up to 0.812 miles which rounds to 0.81. This give the illogical result of 0.41+0.41=0.81. However, increasing the precision will not eliminate this situation. If the precision is increased to 3 points, you may see 0.406 miles displayed for each lap, but the actual distance could be 0.4056. These two laps will add to 0.8112 which rounds to 0.811 leaving us with the same problem (0.406+0.406=0.811).

0 Comage over 14 years ago

I perfectly understand your explanation, being an IT guy myself. Thanks.

Perhaps it could be feasible to sum the rounded numbers up? Or is this not what we want? Otherwise, I believe increasing the precision of the numbers would help to "minimize" the discrepancies.

0 Former Member over 14 years ago

Using TC might help

I transferred the data to The Training Center and had 3 decimal digits and that explained the summing up of the partials.