Lat Long Preferences

[Seevee]

All,


I've been curious lately.
What is the preferred lat long format for boating?
And want format is usable in the common marine mapping softwares (Navionics, Aquamaps, etc?)


I like decimal minutes... easy to read and copy.


Also, is there a way to set Google maps to decimal minutes?


And a good converter that you could paste the whole coordinate without piece mealing it to convert to a different format?



I've had trouble searching Aquamaps with any format, but would be nice when someone gives you coordinates. Often very hard to find places withoutl


Thoughts

 

[O C Diver]

Aquamaps is pretty easy to set to your preference. In the menu, scroll down to the Map Appearance section, second from the bottom should be Coordinates Format.

Ted

 

[Shrew]

Of the three commonly accepted Log./Lat. notation:

Degrees Minutes Seconds (D° M' S")
Decimal Minutes (D° M.M')
Decimal Degrees (D.D°)

I prefer Decimal Degrees. It's just one persons opinion. I don't think there is a wrong answer.

 

[rslifkin]

I grew up with degrees, minutes, seconds, so that's what I was used to and clung to for a while. However, at least in my area, the USCG uses degrees, decimal minutes on the radio, so I've switched to that and gotten used to it.

 

[jgwinks]

Paper charts and thier raster scans usually read to 1/10th minute and you can get pretty close guesstimating the hundredths column, so decimal is easiest there. Electronic vector charts can be set to read whatever you want, but as said above decimal is most common so works better if you have to communicate a position.

Back in the really old days they did things like reading positions in dms and not putting numbers on the compass. This was a deliberate effort to make navigating the ship more difficult. Usually the Master and maybe First Mate were they only ones on board who knew how and it was their anti mutiny insurance. They were the only ones who could get the crew home.

 

[High Wire]

Ddmm.mmm
The last m is six feet per unit.
This question probably would be better as a poll.

 

[mvweebles]

I'm curious, what circumstances are GPS coordinates ever used? I've heard USCG SAR announcements giving the coordinates, but that's a pretty narrow use case.

As a point of paper chart history, since a nautical mile is defined as 1/60th of a degree of latitude, having a distance scale on a chart was unnecessary. Distances were measured using a pair of dividers compared to the scale along the vertical side (latitude) of the chart. It could be further broken down into 60 minutes, and 60 seconds. Deg/min/sec was the only sensible method of notation given the measurement technology at the time

Peter

 

[High Wire]

I'm curious, what circumstances are GPS coordinates ever used? I've heard USCG SAR announcements giving the coordinates, but that's a pretty narrow use case.

As a point of paper chart history, since a nautical mile is defined as 1/60th of a degree of latitude, having a distance scale on a chart was unnecessary. Distances were measured using a pair of dividers compared to the scale along the vertical side (latitude) of the chart. It could be further broken down into 60 minutes, and 60 seconds. Deg/min/sec was the only sensible method of notation given the measurement technology at the time

Peter

The only time I have had to give lat/lon over the radio in the past ten years was to give the CG my position when I heard a mayday. It was ddmm.mmm. Every gps onboard my boat is setup with the same format. It’s kind of important that you communicate the correct units in an emergency to save response time. Saying numbers only without the units can give three different positions to responders.