How to communicate latitude and longitude

[N Harmon]

Experience at a recent SAREX has demonstrated to me that a lot of folks don't know how to communicate coordinates in latitude and longitude. This goes for sending and receiving. I myself may be included because frankly, there is next to no information on the proper way of doing it (inside or outside of CAP). Allow me to demonstrate.

Let's say you are driving down the road and mission base wants your location. You look at your GPS and it says...

N 44° 37' 22" W085° 22' 24"

Here are all of the different ways I have heard the above communicated....

"Forty four thirty seven twenty two by eighty five twenty two twenty four"

"Forty four degrees thirty seven twenty two north eighty five degrees twenty two twenty four west"

I have been taught that the proper way to communicate this is... "North fourty four degrees, thirty seven minutes, twenty two seconds by West Zero Eight Five degrees, twenty two minutes, twenty four seconds".

But most GPS units seem to be programmed to give minutes or seconds in decimals of degrees or minutes:

N 44° 37.223' W085° 22.404'

or

N 44.5840° W085.3233°

And oh boy does it get interesting there....

"North Forty Four Thirty Seven Two Two Three By Eighty Five Twenty Two Four Oh Four"

My favorite:
"North Forty Four degrees Thirty seven minutes, point two two three seconds By Eighty Five degrees twenty two minutes point four oh four seconds"

And the way I say it, which may be just as wrong as the rest, is "North forty four degrees thirty seven decimal two two three minutes by West zero eight five degrees twenty two point four oh four minutes"

Now, I'm not posting this just to let off a little steam at the frustration I have had in decyphering all the different ways in which people transmit coordinates. I know enough about maps and coordinates that I can usually translate. But you know what? A lot of people in CAP can not. And coordinates are pretty important, otherwise we wouldn't bother.

So, does it seem like a good idea that we should try to standardize on a single format, so as to avoid confusion? And wouldn't it be nice if people were trained in the proper way to communicate coordinates...assuming such a "proper way" even exists?

Oh, and on a tangent... Why the precision? I hear ground teams reporting their position in minutes out to three decimal places. If a degree is at most, 69 miles, then .001 of a minute is... umm...  5280*[69/60]/1000 = 6 feet. Really? If you're traveling on the highway, you cover that distance in such little time, is it really necessary? I had my ground team report its position in degrees and whole minutes. No need for any further precision in that context.

And another tangent... Us ground pounders get taught UTM/USNG/MGRS whatever its called today, but we NEVER use it. This despite all of its advantages... it's easier to communicate. Easier to find the distance between two points. Perhaps we simply want to make things easy for the air side.    No j/k, I taught those guys how to read UTM and they had no problems with it.

So, can we standard our coordinates, and does anybody have anything citable as the proper phraseology of latitude and longitude?

[mynetdude]

IIRC the phraseology information you're looking for is in the BCUT training.

"point" is incorrect, "decimal" is correct. and using "oh" as 0 is incorrect it should be pronounced "zero" otherwise you're going to have people like me who THINK they have it correct writing down letters not numbers I prefer simplicity and standards that are the same.

[lordmonar]

First.

a lot of how you pass coordinates is driven by how your planning section and AOBD/GBD want the data.

DDD MM SS or DDD MM.MM or DDD.DDD.

The point being team on the ground or in the air should be pushing data in the format of the requesting agency.

Here in Las Vegas we use DDD MM.MM.  I will push the data like the 113 degrees 23.33 minutes 49 degrees 24.28 minutes. I omitt east/west north/south as our radios are not that good .

Is that "correct"?  Don't know....the MRO's have not had a problem with it.

Always ask for more percision.  If you got GPS and it gives you DD MM SS.SSSSSSSS take it when you can get it.

I find that ground team coordinates via GPS are almost always spot on....aircraft coordinates are always a little spotty (I usually add +/- 1.5 miles from any aircraft GPS).

[Al Sayre]

AFRCC gives  DDD MM.MMM so we use that as the standard.  it's easy enough to convert back &forth if you need to.

[desertengineer1]

I think this is a function of training.

If done right, you don't have to specify any formats - it's obvious from the data.  In addition, you don't need to specify the hemispheres - will they really change?

"thirty five twenty four decimal four eight one"

Writing that as you receive it should be obvious...  35 24.481 --> N 35 24.481 (advanced skillset can approximate N35.41 or N35 24 24)

"ninety eight twenty two decimal seven three five"  98 22.735 --> W98 22.735

But I share your experiences.  I've copied crazy things like N98 32.25  or (my personal favorite) N 35 98.387.  I've circled ground teams for half an hour repeatedly telling them the target is azimuth 030 at 5 miles, and trying to explain to them how to use the compass over the radio after they (and thier GTL) look up at us with distant deer in headlight expressions. 

It's not the cadet's fault.  It's ours for not taking the time to do diligant training and saying "no" to all the distractions so we can get them trained.

We've got a major problem right now, IMHO, that we are doing more local charity activities, parades, and conferences than SAREX'es and FTX's.  THIS is causing a major skill deficiency, and I'm seeing more and more sliding as the years go by. 

We've got way too many distractions going on and it's going to get worse if we don't start saying "no" more often.

[sardak]

From the National Search and Rescue Committee (NSARC), comprised of the federal SAR agencies including AFRCC, Coast Guard, etc., addendum to the National SAR Manual:

a. Latitude and Longitude should be in one standard format: DD-MM.mmm.  If required, use only 3 digits to the right of the decimal; 1 or 2 digits is acceptable.

b. Do not use leading zeros to the left of the decimal for degrees or minutes that require fewer than the maximum number of possible digits to express their value. The minimum number of digits is always one, even if it is a zero. (Example: Not Recommended: 09-00.300N 004-02.450W; Recommended: 9-0.3N 4-2.45W).

c. Latitude is always read and written first noting "North" since the U.S. is North of the Equator. Longitude is always read and written last noting "West" since the U.S. is West of the Prime Meridian.

d. When speaking Latitude and Longitude coordinates for 39° 36.06'N by 76° 51.42'W. Latitude and longitude is stated as: "Three nine degrees, three six decimal zero six minutes North by seven six degrees, five one decimal four two minutes West." The words, "degrees," "minutes," and "decimal" must to be spoken.

From Chairman of the Joint Chiefs of Staff Instruction CJCSI 3900.01C
a. The two coordinate reference systems to be used for reporting and referencing positions (referenced to WGS 84) shall be:
(1) Geographic coordinates using the sexagesimal system, expressed (represented) in degrees, minutes, and decimal minutes (DDMM.mmmm).
(2) The Military Grid Reference System (MGRS). Ground units and ground combat operations shall be serviced with MGRS coordinates. To support homeland security and homeland defense, the federal Geographic Data Committee (FGDC) US National Grid (USNG) standard when referenced to North American Datum 1983 (NAD83) is operationally equivalent to and is an accepted substitute for MGRS coordinates referenced to WGS 84.

The sources for this are on the NSARC website: http://www.uscg.mil/hq/cg5/cg534/nsarc/Georeferencing_info.asp

One can argue, correctly, that NSARC policies and procedures only apply on federal level incidents and that CJCS Instructions don't apply to non-DoD users, so this guidance can be ignored. On the other hand, there is no harm in following this guidance. The problem is that most SAR personnel, in or out of CAP, don't know these exist. And of course, there is a large body of people who don't want to have anything to do with something recommended by the feds.

Keep in mind that Sarsat hits are sent in the format DDD MM.m - minutes to one decimal with no option for any other format. NTAP coordinates, unless converted by AFRCC, are in DDD MM SS.

The confusion over different coordinate systems is an issue. Earlier this year, the NTSB released its report on the Maryland State Police helicopter crash. Among its findings, was "Maryland State Police troopers and System Communications Center personnel were insufficiently equipped and trained to conduct a search involving global positioning system coordinates, and this hindered their ability to locate the site of the wreckage."

NTSB's recommendation from this finding, to many local and national agencies is: "Inform your members through your websites, newsletters, and conferences of the lessons learned from the emergency response to this accident, particularly emphasizing that search and rescue personnel need to understand how to interpret and use global positioning system coordinates..."

Mike

[RiverAux]

AFRCC gives  DDD MM.MMM so we use that as the standard.  it's easy enough to convert back &forth if you need to.

Every CAP aircraft I've been in has their GPS set to that format, so I'd hope the ground teams would do the same.

[mynetdude]

AFRCC gives  DDD MM.MMM so we use that as the standard.  it's easy enough to convert back &forth if you need to.

Every CAP aircraft I've been in has their GPS set to that format, so I'd hope the ground teams would do the same.

I sure hope so myself too, otherwise we'll be doing lots of converting on the ground... I'm on standby for a UDF search as we're waiting for airscrew.

[N Harmon]

AFRCC gives  DDD MM.MMM so we use that as the standard.  it's easy enough to convert back &forth if you need to.

Every CAP aircraft I've been in has their GPS set to that format, so I'd hope the ground teams would do the same.

Hope won't make it happen. As a ground team person, I had no idea that the aircraft used that format exclusively. It's nice to know though. 

I still think that if you're driving or flying and you need to report your coordinates, degrees and minutes are sufficient given that your coordinate "minute" will change in more or less than a minute. Marking coordinates of a fixed location, like that of an ELT, or crash site, or clue...is different.

[desertengineer1]

Absolutely correct from the "exactness" standpoint.  Don't have any arguments on what the standard is, WRT what's written in the AFRCC procedures.

But I'll take a stab at a slightly different angle - an attempt at operational compromise based on what really happens in our - a common sense, efficiency approach.

Everyone who has time in the seat knows we always have conflict between procedureal correctness and brevity.  Seasoned MO's know whoever they're talking to have about 100 milliseconds of collective concentration to take advantage of.  You have to be both quick and accurate.  We've all been there - going through an entire read, again, and again, and again, because the person on the other end heard only the first 10%.  This is where the training comes into play.

As a Mission Base radio operator, for example, you're never going to get a complete, accurate exchange of messages doing it word for word, in the time you've got.  We've tried it many times, always with brutal results.  There are so many time variant barriers to communication in the chain.  You've got to be quick AND accurate.

Here's an example of good brevity when everyone is trained.  First, everyone should know that we're in the Northern and western hemispheres.  They should also know that in CONUS, Lat and Lon are not really interchangable.  Not trying to be "uppity" but anyone working with coordinates should recognize the problem with N 98 34.1 or W 78 112.02.  I can get into the many reasons why AFRCC and DoD does it the long way, but those don't really apply to CAP.  (We don't have INS's, radars, sniper TGP's, or dual PID ROE's    )

"North" and "West" are not absolute requirements when passing lat/lon - functionally speaking, in CONUS.  You know you're in the Northern and Western hemispheres.  You should know the approximate lat/lon you're working in (within a couple of degrees each) as well.  Application of this situational awareness SHOULD either prevent aggregious mistakes in translation or (on the positive side) allow for optimized brevity in both initial transmission or when readbacks are required. 

98 21.3 105 24.1 is therefore an easily recognizable number.  Even 98 22 35 105 38 20 will work, functionally.  You should know that you are approximately 98 30 / 105 45.  You should be able to quickly find this location on any chart, and you should know planned or expected location regions of your ground/air units.  Therefore it should be an obvious issue if you see 105 30 98 10, or 98 75 105 98, or something similar.

For formatting, yeah, I totally agree with the other posts that you've got to attempt a line somewhere on formats.  A properly trained GTL's competancy should be knowing how to set GPS field formats to DD MM.MMMM, or at least converting to it in a crunch.  A competent IC or Branch Director should also be briefing the required standards.  A well seasoned MB radio operator should recognize and ask for clarifications, etc...

This all boils down to training and competency.  Practice.  Feedback/mentorship.  Practice.  Practice.  Practice.   Which we seem to have less every year.

[desertengineer1]

Oh, and along those same lines....

Another one I see is the assumption that 1' LONGITUDE = 1 nm, when plotting things "on the fly".  It was kind of funny.  When I said "That's only on the equator, sir.  Essentially, the East-West distance at our latitude is proportional to the Cosine of the latitude, therefore this [pointing at chart] would be approximately 5 miles, not 10."

I never got invited to fly with him again 

[scooter]

Whatever format you use, don't speak any faster than you can write! You will have to repeat it if you dont speak slowly so the cadet on the other end of the radio can copy the first time.

[Eclipse]

I require all my Ground Teams to report their positions in Universal Transverse Mercator, and only use compasses (compi?) that are marked in Mils Radian.

[mynetdude]

I require all my Ground Teams to report their positions in Universal Transverse Mercator, and only use compasses (compi?) that are marked in Mils Radian.

Then you are only making it worse for those who are not trained to receive & convert UTM but then I guess regulation doesn't say you can't use UTM

[shorning]

I require all my Ground Teams to report their positions in Universal Transverse Mercator, and only use compasses (compi?) that are marked in Mils Radian.

Then you are only making it worse for those who are not trained to receive & convert UTM but then I guess regulation doesn't say you can't use UTM

That's okay...I require mine to provide coordinates using the Clarke 1866 datum.

[Spaceman3750]

and only use compasses (compi?) that are marked in Mils Radian.

They make compasses displaying radian measure? I would get one, but I also don't want to be forever haunted by this algebra/trig class...

[Eclipse]

I require all my Ground Teams to report their positions in Universal Transverse Mercator, and only use compasses (compi?) that are marked in Mils Radian.

Then you are only making it worse for those who are not trained to receive & convert UTM but then I guess regulation doesn't say you can't use UTM

OK, seriously?

[RiverAux]

You thought you were joking, but I remember at some point in my CAP career a so-called ground team "expert" advocating using UTMs.  The reasoning, IIRC, was that it was "the military way".  This was a while back though.

[N Harmon]

There are tons of good reasons to use UTM/USNG/MGRS, especially if you're on that rare ground team sortie where most of your time is spent on foot.

[Eclipse]

There are tons of good reasons to use UTM/USNG/MGRS, especially if you're on that rare ground team sortie where most of your time is spent on foot.

Let's here it.   Folks - I was kidding.

Most of our navigation and reported azimuths are +/- 5° and everything with a battery these days has an integrated GPS that reports Lat / Long.  1/3rd of the country doesn't even need to compensate for magnetic declination.

Nothing we do requires or even supports the use of devices that provide the additional accuracy of UTM or Mils-Rad.