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13,645 Posts
Brad, why don't you get a new freezer that can display the temperator the modern way, in degrees Kelvin? There's an ISO standard for ice cream storage that....(VBG)....

"That said, it would help if the format were communicated somewhere."
Uh, but seriously, every co-ordinate system has a proper format and syntax and if any one of them is written out "correctly" with the correct glyphs and syntax, it should always be unmistakable for any other format.

For the DD MM SS format, that means *always* including the correct glyphs for those, even though some computer systems and character sets don't allow for ° ' " or ° ʹ ʺ (which should be two different sets of glyphs) even if the user wants to find them. And part of the reason why a lat/lon position in traditional navigation will always be DD, DDD with a lead zero if necessary in the longitude to redundantly identify it as longitude even if the E/W gets left out.

I'd have to wonder if the character set that the satellite systems use allows for the proper glyphs, but I'd hope the SPOT people did some of their own process control to make sure errors like that were unlikely to happen.

393 Posts
Overall, it's a pretty neat gadget. I just wish it had an option that permitted you to select the location convention of your choice. (more snippage)
I think those two sentences sum up the whole thread.

Gary is used to DD MM SS, and that's what I grew up learning, as well. But the advent of GPS changed all of that. Your chartplotter display may show DD MM SS, but the GPS inside it actually uses (Degree Minutes), and only converts it to DD MM SS for your display. This of course makes sense for a chartplotter on a boat, as it makes it easy to correlate to a paper chart. BUT, for communicating the position to other devices, either within your boat network or via an AIS transponder, the NMEA sentence for GPS location uses Degree Minutes, and looks like this:
Geographic Position, Latitude / Longitude and time.


Which means:
4916.46,N Latitude 49 deg. 16.45 min. North
12311.12,W Longitude 123 deg. 11.12 min. West
225444 Fix taken at 22:54:44 UTC
A Data valid
So, as somebody pointed out earlier in the thread, there are three different conventions used (actually, I believe there are at least four, as Loran C is different, as well).
Ultimately, everybody ought to get used to the Decimal Degrees (DD.dddd) format. It is THE de facto standard for electronic position reporting around the world. The various networks that track AIS data report it using Decimal Degrees, even though the transponders themselves use Degree Minutes, apparently because that's the format in NMEA. :confused:

Here's info from, which uses AIS data:
There are at least 5 alternative methods to enable position reporting for your vessel:

1. AIS Transponder
2. mAIS: iPhone and Android self-reporting app
3. Email position reports
4. Satellite or 3G/GSM locator devices
5. AIS transponder/receiver on board, connected to the Internet

1. AIS Transponder The positions of the majority of the ships displayed on are based on the collection of AIS (Automatic Identification System) signals transmitted by AIS transponders installed on board vessels. All vessels over 299GT are required to carry an AIS transponder on board, which transmits their position, speed and course, among some other static information, such as vessel’s name, dimensions and voyage details. Smaller vessels may optionally use the lower cost ‘Class B’ AIS Transponders to transmit AIS signals.

AIS transponders transmit periodically this information on VHF radio-frequencies and make this data available to the public domain. Our network of AIS receivers collects this information and publishes it on our web site.

The limitation of this method is that a ship must be within the range of one of our AIS receivers (i.e. at a distance smaller than 30 nautical miles from a receiving station on average) in order to collect and display her position.

3. Email position reports We are accepting position reports by email messages sent to [email protected]. If you have either an established automated procedure to send email position reports or you wish to manually send your position to MarineTraffic, you may consider including the above email address to the recipients of your position messages.

Email position messages must be sent on regular intervals to [email protected] in order to be able to display a continuous track of your vessel. Ideally, the message interval should be less than 15 minutes, but an interval of one hour or more is acceptable.

In order for us to be able to parse your report, the message should be preferably written in a standard format like the following:

TIMESTAMP=2012-03-03 02:13
(Latitude and Longitude in decimal degrees – negative values for South or West coordinates. Speed in knots. Timestamp in UTC time)
So, the AIS system is using decimal degrees. I haven't been able to find a source yet, I want to see if EPIRB uses the same format. BTW, can also use DD MM SS info if you self-report (email, e.g.) your position that way, it just gets converted to decimal degrees. :)

Senior Member
11,861 Posts
I never say a write up yet or a user claim it was as effective and comparable to an EPIRB or Individual one.

Its a great toy. I bought one when they first came out and thought after using it it was a great gimick to let others know APPROX where you were, but if I was in the drink or in a liferaft I would want the real thing...and EPIRB.

You get what you pay for

QUOTE=caberg;1698122]I have to wonder who was writing those writeups. I've never seen this suggested anywhere.[/QUOTE]

5,097 Posts
So where are you old guys getting charts with seconds on them.

Have you had them for 30 years.

I looked at all my charts and I've got a lot of them and they all have minutes and the minutes are divided into tenths.

I looked at Richardson charts and some print on demand charts.

Degrees, minutes and decimal minutes.

Are you going to a special old guy store?:)

6,663 Posts
Discussion Starter #85
Dave, one of the problems with being old, other than health issues, is a lot of the stuff we tend to accumulate is damned near as old as we are. Additionally, when I learned navigation I was only 17 years old, 1957, and in the U.S. Navy. The charts they had back then were probably at least as old as I was. Obviously, my mind has not completely gone to Hell, yet, because I can still manage to find my way to the Florida Keys from the upper reaches of Chesapeake Bay using those ancient charts, 39-year-old boat, 35-year-old compass and 5 year old GPS/Plotter.

I talked with my old buddy who is a retired USCG captain who said, yeah, the USCG is all digital for navigation these days and has been for quite some time. He said it really doesn't make any difference, because they can recognize the various conventions as they come in to them electronically.

Gettin' old ain't fer wimps and sissies,

Gary :cool:

Old soul
4,509 Posts
I have one chart that I use which is in DDMMSS format. All the others are The number of charts that are in DD.dddd format; none, zero, nada, zip.

DD.dddd is perfect for computers, but until we all go 100% digital, it only makes sense to communicate in "at the human interface" ;). Technology should conform to user's needs, not the other way around!

... so there :batter
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