I was taught that there are two conventional ways to denote marine
1. The somewhat outdated Deg Min Sec as in N44° 40 (min.) 30 (sec)
written as N44 40 30 with NO decimals
and pronounced as North forty four degrees forty minutes thirty seconds.
This defines a position within 60ft
2. Due to earlier digital eqpt limitations-(they couldn't compute seconds at first)
The modern system of Deg Min Dec. of a Min) as in N44° 40(min) .50
written as N44 40.50
and pronounced as North forty four forty decimal fifty
This defines a position within 60ft.
If you wish to bother with the 3rd digit in your GPS
display of . sec or .01min (both 6ft) then I guess it would be OK to add a dot (decimal pt.) after the 2 digit seconds in example 1. above as:
N44° 40 30.5 & pronounced as
North forty four degrees forty minutes thirty decimal five seconds
though I can't think of a good reason why you would want to.
In the days when degrees minutes seconds were commonly used,no mariner was able to get down to 6ft.
With the advent of DGPS/WASS, 6 ft became possible-& decimals of a minute replaced seconds. as in :
pronounced North forty four forty decimal five oh five.
When working with old charts
that are marked in degree min. second format,it is advisable to be able to convert seconds to decimals of a minute for communication purposes.
It's very easy:
60sec = 1 minute
30sec = half a minute = .50 min.
15sec= qtr of min. = .25 min
Just divide the actual seconds by 60
This is my understanding for marine navigation