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Board » Technical Support » Is the DTG calculation correct

Posted by
mwagg56


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2009-03-23 23:12:20
2009-05-22 05:03:29 - Is the DTG calculation correct
Is it just me but does the DTG calculation seem incorrect. Seems to be too much north of the rum line!
Posted by
jakob


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2007-09-04 10:05:30
2009-05-22 05:46:31 - Re: Is the DTG calculation correct
DTG is calculated along a great circle (shortest way) and not the along rhumb-line (constant course). ok?
...one of the guys behind the game...
Posted by
mwagg56


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2009-03-23 23:12:20
2009-05-22 05:59:59 - Re: Is the DTG calculation correct
I understand. However, checking with the great circle tool suggests that the DTG for boats above the rum line is incorrect. eg STU131270 is reading around 917nm to go but the great circle tool suggests the true distance is about 100 nm less.
Posted by
jakob


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2007-09-04 10:05:30
2009-05-22 06:42:53 - Re: Is the DTG calculation correct
DTG-calcs over long ranges when rounding of waypoints are involved are tricky. Just be cool and things will sort out as you get closer, I promise.
...one of the guys behind the game...
Posted by
Incognito


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2008-12-06 13:43:52
2009-05-22 07:34:48 - Re: Is the DTG calculation correct
Hi SOLer's,

I have just opened a similar thread. Sorry to repost here.

Jakob, I do not want to be mean, but you seem to be in denial. ;-)

According to SOL, at 7:00 UCT, I was ranked 86th with more than 674 NM to go.

In brainaid's ranking however (http://sol.brainaid.de/pub/ranking-145.html), I was ranked 14th with 637 NM to go.

Quite a difference! And when I use the pliers or the pointer to calculate the DTG, I come to a figure similar to brainaid's.

We had similar issues in led 5. Personnally, I remain convinced that there is an error in the formula used to calculate the DTG in SOL's ranking. It would be nice to fix that sometime.

Regards,

Francois on Incognito

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