Simple question. (I think) GTC / GP3S / GT31 related.
GTC requirements for Distance are in Km. If the GT31 is setup for speeds based on knots, does that mean the GT31 is calculating its distance / speeds etc based on nautical miles.
Example.
On GP3S UK units are set to show distance in Miles, when I change the settings to show distance in Km, it would appear the calculation to do this is using distance based on miles and not nautical miles.
ie. Mark Bailey session (14/03/2010)
Distance=16miles, change GP3S units to km = 25.74km
However 16 nautical miles = 29.63km
I'm not quite sure which value to post on GTC ..... ok it's only a small difference on the lower numbers, but once larger numbers are acheived .. that could make a difference.
cheers
H
there are different miles
a mile is roughly 1.6kms
and a nautical mile is 1.852 km's
is your discrep here?
Can't speak for how the other software works, but www.ka72.com/ performs all its calculations internally in m/s and displays results in whatever unit it is set to display, so in the free site, distance is always returned in km (whereas other speeds are in knots.) All GT-31 distances are in doppler.
Not to blow my own trumpet too hard
, but the site now allows you to post direct to GPSTC from your upload. That would tend to reduce the potential for human error.
The discrepancy you mentioned is almost certainly due to the difference between nautical miles and land miles. I suspect the GP3S UK units are in miles as a nod to the archaic UK road system (speaking as an expat, I am allowed to knock it.
) Are board displacements in litres or pints?
hmmmm....
I 've just checked my data on GP3S and Steve Thorps' session from the 26th Feb @ Southend.
Taking Steve's session.
Distance = 25 Miles
Now the question is ..... is that 25 nautical miles or 25 road miles. As our GT31s are set to NM I presume that figure that has been computed through GPS Results is based on Nautical Miles.
25 Nautical Miles = 46.3 Km
25 Road Miles = 40.2 Km
Steve's GTC data for that session = 40.45 Km
Still trying to work this out ..... Now checking Pete Youngs' (The Matrix - Portland Pirates) Session from the 20th March
GP3S Distance posted = 43 Miles
GTC Posted Distance = 69.58 Km
43 Nautical Miles = 79.63 Km
43 Road Miles = 69.18
GP3S Unit conversion from Miles to Km
43 Miles converted to Km = 70 Km
hmmm??????
How did you post to GP3S?
Automatically?
If so then the distances posted are probably correct in km.
Happy to double check any tracks if you want to send them to info at gpsteamchallenge dot com dot au.
@ Nebs,
Whilst we are on the subject, following on from Mike's comment, is there a requirement in GTC for min GPS speed setting for logging data. I ca'nt help but think of the number of speed spots around the world, especially when sailing broad to super broad that involve as much walking as sailing, usually back up wind, therefore total distance logged = 50/50 sailing / walking. hmmm.
@Dylan, thanks for the info, we had a look as KA72 a few months ago .... sounds like a re-visit is required 
..... not had a need to use the GPS for nearly 6 months!
OPH,
As Dylan mentioned, his KA72 auto-upload eliminates potential for user error in transferring data manually. Best thing since sliced bread in my opinion and maybe the GPSTC hierarchy could look at making it de rigueur for logging of all sessions. Certainly put everyone on the same level playing field and would allow anyone to download other members tracks for analysis.
PS - I reckon if you have to walk back to your start point during a session then including 'non-sailed' distance isn't an issue. Seriously at most you'll only do it a maximum of 10 times at a maximum of 1km each time. Any further and you'd have some serious chafing issues to deal with (well I would anyway).
If you want to increase your distance by walking your kit instead of sailing it, then good luck to you!
It's more a handicap than an advantage...
In the scheme of things it really doesn't matter. I always claim distance walked because I couldn't be @rsed finding the bits that I was walking, as opposed to slogging...
Just use the total distance from when you turned it on to when you stopped. And have fun!!
