true story - why knowing UTM coordinates can be helpful

Cartography, maps, navigation, GPS and more.
Post Reply
User avatar
Posts: 50
Joined: July 30th, 2015, 9:41 am

true story - why knowing UTM coordinates can be helpful

Post by johngo » December 15th, 2016, 9:56 am

Here is a story about how knowing UTM coordinates can be helpful in the backcountry.

Some years ago, a group of about eight people were on a technical mountaineering trip in the North Cascades.
One member of their team slipped on some wet rock, took a tumble, and bonked her head.
The remaining team members decided she was injured enough to call out for a helicopter.
No one had a GPS, but they did have a map with a UTM grid, and they knew their position.
They determined their UTM coords, accurate to about 100 meters, and called this out to 911.
911/County SAR responded a short time later saying that terrain was too steep to land a helicopter, but there was a flatter spot that they knew of about a half mile away, and requested the climb team move the patient to this location.
SAR told the climbing team the UTM coords for this landing zone.
The climb team plotted these coordinates onto their map, again accurate to about 100 meters, and carried their injured patient to the landing zone.
The helicopter came in for a pick up, everything worked out fine.

So, a few good lessons came from from this.

Having the ability to determine your coordinates by looking at a map to tell 911 your exact location, and then being able to plot the coordinates 911 gave and hiking to the landing zone, were some pretty important skills to have. In addition, even though the 911 operator may or may not have known what a UTM coordinate was, once that information got out to the proper SAR folks, they were able to interpret it and respond accordingly.

User avatar
Posts: 1291
Joined: July 23rd, 2011, 8:31 pm
Location: Oregon City

Re: true story - why knowing UTM coordinates can be helpful

Post by forestkeeper » March 13th, 2017, 8:04 am

Maybe that was before backcountry transponders were in existence. But it is very wise to carry a topo map of the area you will be in and be able to plot your course as well as be able to report your location (to SAR) if need be within 10 meters, not 100 meters. Latitude/ longitude bearings are a necessity.

User avatar
Posts: 50
Joined: July 30th, 2015, 9:41 am

Re: true story - why knowing UTM coordinates can be helpful

Post by johngo » March 21st, 2017, 8:59 am


It happened after wilderness transponders / Spot /inreach were invented. But those suckers are expensive and require a $$ annual service contract, so not everyone will choose to carry them.

This post was more of a reminder to folks to learn about about UTM coordinates because doing so may just save your bacon someday. They are much more ussr friendly than lot long coordinates when it come to actually plotting coordinate onto a map.

Finally, in most any type of "report your position to SAR" scenario that one can imagine, reporting your position accurate to 100 meters is going to be just fine. Being more precise with a position down to 10 meters is tough to do by eyeball alone. It's sort of like a car speedometer telling you you are going "57.8 mph" - yes, it's more precise, but that precision is not really helpful to most drivers.

Posts: 1260
Joined: May 28th, 2008, 10:03 pm
Location: Aurora

Re: true story - why knowing UTM coordinates can be helpful

Post by Lurch » March 22nd, 2017, 7:35 am

Actually since most speedometers have 5-10 mph tick marks, it would be more like saying you're going 57...

I've said before, UTM's are great, they most certainly are the primary coordinate system in the region for many reasons. BUT 911 dispatchers are not familiar with them, and most likely will not know what you're talking about. Taking the time to attempt to explain it to them will be needlessly confusing, risks simple errors due to lack of familiarity, plus it kills your battery. They can ping cellphones far more reliably now anyways and would prefer that most of the time, and are readily familiar at least with the format of Lat / Long D.ddd° Or you could learn how to take a screen shot of an appropriate mapping app that shows your coords and text that to the SAR coordinator who's most likely going to call you back anyways.

Helo's also aren't fans of UTMs. They shouldn't be using them, it doesn't make sense for long distance travel. As a result they have little training (if any) with them, and they'll end up converting them back into D.ddd° anyways.

Frankly speaking, if you're talking to a SAR person and you can tell us what coord system and map datum you're using, we'll take anything you can throw at us. If you're not talking to a SAR person, I would stick to common general use systems like Lat Long D.ddd° in WGS84

User avatar
Posts: 50
Joined: July 30th, 2015, 9:41 am

Re: true story - why knowing UTM coordinates can be helpful

Post by johngo » March 24th, 2017, 2:54 pm


Those are excellent points, and it's a good reminder to all - when possible, report your position to 91 using lat/long decimal degree coordinates, which, for the top of Mt. Hood, look like this: 45.3734, -121.6959.

For most folks, you are going to have to get these coordinates from a GPS, or at last a GPS type app on your phone.

The point of my original story was that NOBODY had a GPS on this trip, and thus could not get their coords in decimal degree format from the map. But they could using UTM, so they did, thus happy ending.

iPhones show your coordinates on the native Compass app, but they are in degree minute second format.
Better than nothing, not the same format suggested by Lurch.

A simple iPhone app I like is called "UTM Mailer".
It shows:
your lat long coords in the preferred decimal degree format
your UTM coords (Zone, Easting and Northing)
the approx accuracy (eg, "+/- 33 feet")
and lets you email or text a message along with the coordinates.

The app was free for a long time, now it's $2.
See details and screenshots here: ... 06003?mt=8

It's a small bit of cheap and weightless insurance to carry along if you ever may need to transmit your exact coordinates to someone.

PS - Oregon 911 call centers cannot all take text messages, so do NOT rely on texting them for help. Send it to a friend at home, and have them pass it along to 911.

PPS - I have seen a car on a test track with MPH shown out 1 decimal place, so they exist. =^)

User avatar
Posts: 9
Joined: May 6th, 2010, 11:44 am
Location: Salem

Re: true story - why knowing UTM coordinates can be helpful

Post by eddiecoyote » June 24th, 2017, 10:11 am

I agree.

I teach land navigation skills to US Army infantry, including a bit on map reading, plotting, etc.

In our training we will do a 12 mile ruck march in under 5 hours, with minimum 68 lbs of gear, then add weapons, and go. Some people are not prepared for the demands of this weight and we regularly have a person or two drop.

One night a person fell out, rapid pulse, conscious levels were low, etc... and we initiated our safety protocols. I was the trailing instructor, sweeping up, and I instructed the medics to begin their thing. For medical emergencies we call 911 and meet them at the front gate.

I called 911 and told her the Umatilla Army Chemical Depot. It's only been around for decades and everyone in the area knows it. She asked what county was it in. I didn't expect that question. I'll sometimes go geocaching and I knew that a nearby geocache was on the county line and that we were either east or west of that line. But that didn't help us out. I told her I could give her a 10 digit MGRS (UTM) grid. She didn't know what I was talking about. I told her I could give a latitude/longitude. She said she needed a street address. So I googled the address on my phone while she waited and told her.

We got the soldier to care. But it was a reminder that you can have all the bells and whistles and some others still can't carry a tune. Be prepared for others. I've since added the postal address to language of our safety plan. Just in case.

Post Reply