GPS Coordinates on the footage

[M8TJT]

Not sure you got that right?

Using the distance calculator at https://www.movable-type.co.uk/scripts/latlong.html ,
the distance between 00 00 00.0N 00 00 00.0W and 00 00 00.1N 00 00 00.1W is 4.3 meters

. But that is a diagonal so not relevant

or between 00 00 00.0N 00 00 00.0W and 00 00 00.1N 00 00 00.0W is 3.0 meters

The actual figure given is 0.003089 km = 3.1m. Either N/S or E/W at the equator.
Now to find out where the discrepancy is. There is no discrepancy between your figures and mine. Mine = 0.036sec = 1.1m Multiply 0.36 by 2.7777 to get 0.1 sec and and multiply 1.1m by 2.7777 gets you 3m

Our dashcams aren't accurate to closer than 3 meters so only 1 decimal place is required...

Whilst I agree in principle, that is only true in DD:MM:SS notation

clearly Google Maps also believes that only 1 decimal place is required... and if I was typing it in then I wouldn't normally bother with the decimal place because 30 meters is normally close enough for me to find the location on the map. Plus it only updates once a second and on the motorway I will be moving faster than 30 meters per second!

OK you win that one more or less. We were comparing the difference in 'accuracy' between D.d? and DD:MM:SS.s? Only one DP when using DD:MM:SS.s notation will give a position to within 3m (N/S) as you say, and 5 DP when using D.ddddd will give a position to within 1m (N/S). So the positional 'accuracy' between the two notations differ by a factor of approximately three when the more significant bits are ignored.

I now rest my case.

 

[Nigel]

...So the positional 'accuracy' between the two notations differ by a factor of approximately three when the more significant bits are ignored.

I now rest my case.

Only if the GPS is accurate to within 1m, which it will not be, except by chance, and chance doesn't help since you will never know if it was or wasn't!