What is the Emergency Services Preferred GPS Coordinate Format?

Submitted: Friday, Apr 03, 2009 at 19:34
ThreadID: 67497 Views:9372 Replies:8 FollowUps:4
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This has bothered me for a while & there was other discussion on EO re Coordinate conversions, which is why I have asked this question.

At least twice now I have heard the Police responding to lost people or an EPIRB response request & in both occasions, the GPS coordinates supplies, did not match the format required by the software that they used. In one occasion they used the interent to find a conversion program so they could then find the location. Luckily it wasn't an emergency....

Also what is not known it seems is that you can't round off cooridinates in order to get an approximate position, the error is way too large.

Does anyone for sure, know the preferred cooridinate format...

Degrees (e.g. 35.1234567)
Degrees Minutes (e.g. 35 10.12345)
Degrees Minutes Seconds (e.g. 35 08 34.231212)

(these examples are not equal locations)

Police?
Ambulance?
Fire?
SES?
Others?

Thanks
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Reply By: Robin Miller - Friday, Apr 03, 2009 at 19:52

Friday, Apr 03, 2009 at 19:52
I don't if their is an offical common standard StormyKnight.

But our Vic CFA maps only have UTM.

Sad to say but in many areas its a bit of a joke , many emergencies services
do'nt know about GPS yet, and many rely on ad hoc private Tom-Toms etc if donated funds
stretch that far.

This year I have come up against the following 3 incidents on the ground.

1/ CFA in smoke - no instruments at all for direction or position finding.

2/ SES crew in search - sent a mate to local caravan park to get a mud-map of area to help with search.

3/ 5 south aussie CFA crews all together at a vic fire scene - not one knew where they where.
Robin Miller

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AnswerID: 357923

Reply By: Member - Mike DID - Friday, Apr 03, 2009 at 20:11

Friday, Apr 03, 2009 at 20:11
All Rescue and Fire Helicopters I've worked with use Degrees Minutes or DMD - 35 10.123

All Marine services use Degrees Minutes Seconds DMS - 35 08 34.2

All Land based services use UTM (0123456 7890123) or MGRS (23456 90123) usually given as a 6 figure grid reference (234 901).

Fortunately we mostly don't have to worry about the Datum conversion mostly - GDA (land units) is close enough to WGS84 (air and marine)

I found that NSW Fire Brigade have a problem if it's not on the UBD maps - all they would recognise was "xx kilometres from Brookly at 215 degrees".



Seven figures for DMD or DMS is generally accurate enough.
AnswerID: 357927

Reply By: toyotabits.com - Friday, Apr 03, 2009 at 20:37

Friday, Apr 03, 2009 at 20:37
G'day all, this is the reason for my last enquiry (thread 67441) - confusion!! Why are there variations? Degrees, minutes, seconds are most common! Why should anyone change it? old & new gps are capable of this system - why change it!!? Can we make a standard, for ALL USE, either or any! A standard we can all use & rely on! without searching or changing to be sure which is one is correct! We only need one that we can all rely on, either, or? just a common system will do!, so now I will step down off my soap box, thanks, regards, aussiedingo
AnswerID: 357932

Reply By: Member - Stephen L (Clare SA) - Friday, Apr 03, 2009 at 20:46

Friday, Apr 03, 2009 at 20:46
Hi StormyKnight
I know a couple of guy's in the local SES and they work on UTM Coordinates.
If push came to shove in any emergency, it would not matter what you were using, providing you know where you are, that will give that as a starting point for their search.

Cheers

Stephen
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AnswerID: 357935

Reply By: Luke2 - Friday, Apr 03, 2009 at 21:15

Friday, Apr 03, 2009 at 21:15
your decent GPS will do any format conversion for you. (all hand helds and any vehicle GPS with the capability to select either UTM or any of the lat/long formats).
the user selects the lat/long or UTM format that the coordinates arrive in from your source. then create a waypoint for that coordinate. then change the GPS format to your preffered format and view the same waypoint - it will now show the same position in the new format.
have i explained that clearly? here's an example.
A search coordinator is told that the victim is at 634-784 on the Dalhousie 2nd series map (this is a UTM grid reference). The search coordinator turns his GPS on, changes the format to UTM and enters the given location as a waypoint. Then because he's going to respond a helicopter and he knows helos prefer lat/long in the degrees and decimal minutes (eg 35 10.1234) he changes the GPS to that format and he reads off the lat/longs to the helo pilot.
AnswerID: 357938

Follow Up By: Luke2 - Friday, Apr 03, 2009 at 21:21

Friday, Apr 03, 2009 at 21:21
PS - it's a nice idea that emergency services might standardise coordinate formats but I've been in and around search and rescue organisations enough to know that it will never happen.
But because the above conversion is relatively easy (as long as your GPS allows you to select the format) then you can quickly do it yourself if the need arises.
I teach my teams (some of my work is to provide first aid response teams for remote events) to do the conversions in case they need to supply a different format for an evacuation and once they do it once it's easy.
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Follow Up By: StormyKnight - Friday, Apr 03, 2009 at 21:33

Friday, Apr 03, 2009 at 21:33
Yes I do a similar thing with OziExplorer regularily since the waypoint dat a can be in a number of different formats.

Its just that from my experience, with the Police anyway, thier system cannot handle different formats on the fly.

Monitoring the information between the Radio Base & the 'rescue' vehicle, it becomes clear that if the coordinate is not supplied in the right format via 000, then the search is delayed & sometimes the search begins in the wrong area, which can also mean in the wrong command area too.

On one occasion it was up to the search vehicle to get the coordinates & try & work it out themselves...

Its just a bit all to hit & miss, & if I'm in need of help, I want to know in advance that when I ring '000' that my call will be acted on immediately. I'm also guessing that if escalted to a true emergency, then i will be found pretty quickly, as the resorces will be implemented to work out where I am, but in the cases I have heard, it wasn't an emergency, but vehicles were sent immediately to locate these lost people. They spent hours searching in the wrong area.

The other issue is I believe all the police had was a direction finding GPS, i.e. no topographical maps, or even street guidence may have found them since they where on a road in a forest but they didn't know which way was home.

Stormy







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Follow Up By: Member - Mike DID - Friday, Apr 03, 2009 at 21:41

Friday, Apr 03, 2009 at 21:41
"your decent GPS will do any format conversion for you"
- that's right, the technology can do - finding people who know how to use the available technology is the problem.

Another example of people limitations - an experienced operator was asked to send the destination Lat Lon - the navigator queried the destination - why ? The position was received as 35 10.12, but the communications operator read it out as 35 degrees, 10 minutes, 12 seconds - because KNEW that Lat Lon was in Degrees, Minutes, Seconds.

Lesson learnt - send as you received it, OR query the source - DON'T ASSUME.
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Reply By: The Explorer - Friday, Apr 03, 2009 at 21:53

Friday, Apr 03, 2009 at 21:53
Hi – there shouldn’t be a standard preferred format (if there is) - one would hope those involved in emergency services would be properly trained and understand the various coord systems and datums in use. Relatively cheap GPS mapping software is available that accepts any coord systems/datums and I am lead to believe many use it already . Setting a standard prefered format and expecting the public to use it is would be an impossible dream.

Cheers
Greg
I sent one final shout after him to stick to the track, to which he replied “All right,” That was the last ever seen of Gibson - E Giles 23 April 1874

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Follow Up By: geocacher (djcache) - Friday, Apr 03, 2009 at 22:18

Friday, Apr 03, 2009 at 22:18
Yeah. One would hope that but they are not.

This is a pipe dream at this point.

Ambulances in rural Vic are equipped with GPS as part of their radio system. It is a readout only and reads in Degrees, Minutes, Seconds. Few ambulances carry handheld GPSr's and only where local funds have bought them. Only those have the ability to plug in a set of coords to pinpoint a location and I suspect they are used in what ever format the operator is happiest with.

Coords are given to Vic Ambulance Helicopters in that format.

Map references from paper maps are in UTM grid.

Depends on the staff you get on the day as to what level of understanding you get.

I pushed for GPS interpretation and electronic mapping training a few years ago and gave up after the bruise on my forehead got too big.

Dave
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Reply By: geocacher (djcache) - Friday, Apr 03, 2009 at 22:20

Friday, Apr 03, 2009 at 22:20
Not only do you need to know what format the coords are in but also what datum the gps is set to.

In heavy tree cover a 200m error is enough to make a search from above by helicopter very difficult.

A 200m error can be achieved by wrong datum or misinterpretation between dd.mm and dd mm ss

Dave
AnswerID: 357947

Reply By: StormyKnight - Saturday, Apr 04, 2009 at 18:19

Saturday, Apr 04, 2009 at 18:19
So to summurise it appears as though those to be rescued need to have an understanding of the different formats for thier own sake, which I guess is a part of being trip prepared.

The other issue pointed out was the assumptions....

35 degs 10.56 minutes
being interpreted as
35 degs 10 minutes 56 degrees

a difference of 690 meters in this example, it could be up to 1 km.

The 3rd issue is the chinese whipsers & the fact that you are often talking to an operator that then has to write the information down & then forward the information on.

Looks like the safest thing would be an EPIRB with the inbuilt GPS...


AnswerID: 358047

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