If you want to avoid getting lost in the backcountry, you need to carry a map (and a compass) and know how to read it. The moment you start using maps, you’ll run across the problem that people have been having since maps were invented.
Maps are flat. The world is round.
Yes, we know that it’s possible there are some folks out there who still believe the world is flat. We know someone who was a proud member of the Flat Earth Society for years. We trust that you are not a member.
The issue with maps is that you can’t spread a piece of flat paper on a round world without crinkles. Even if your map covers a very, very small area, believe that it still has to crinkle, even if it is cut to lessen the problem.
Finding yourself, v1: Lat/Long
It’s hard to find yourself on a flat map depiction of a spherical world. To make it easier, starting in the 1400’s, a series of really smart people (including Amerigo Vespuci, Gallileo Galilei, John Harrison and others) took about 200 years to come up with a geographic coordinate system. This system was called latitude and longitude.
One of the problems of lat/long is units. You can give a location in lat/long in at least 3 different notations: “hours minutes seconds”, “degree decimal” or “minute decimal”. For instance, Barrier Dam Day Use Area is
- 51° 1′ 52.878″ N, 115° 2′ 14.145″ W in hours-minutes-seconds notation;
- 51.031354, -115.037262 in degree decimal notation;
- 51° 1.881’, 115° 2.236’ in minute decimal notation. This is the system used internally by your phone.
Some people shorten the hours-minutes-seconds notation to “52.152878, 115.212145”. This is a really bad practive, because it looks just like (and can be confused with) degree decimal notation. The only difference is that, where we are, the longitude is always negative. On the other side of the planet, it isn’t, though, leading to mass confusion.
All of this notation variability makes lat/long very confusing and easy to get wrong. Read a lat/long to someone and they will always ask you what the units are. On some devices, it’s hard to tell.
Introducing UTMs
To make things easier (and, coincidentally, more precise), in the 1940’s, the US Army Corps of Engineers came up with a new system called the Universal Transverse Mercator system, or UTM.
The UTM system divides the surface of Earth between 80°S and 84°N latitude (where most humans hang out) into 60 zones. Each is 6° of longitude in width (the divisions are shown on the map to the right). Zone 1 covers longitude 180° to 174° W. Zone numbering increases eastward to zone 60. Within 10° of the poles, everything converges so much that the system breaks down, so if you’re planning on hiking to the North Pole, don’t use UTM.
By using narrow zones of 6° of longitude in width (that’s 800 km wide at the equator, much less this far north), the amount of distortion is held below 1 part in 1,000 inside each zone. This is a technical way of saying “it’s easier to be more accurate using UTM than lat/long.” And UTM is metric based, and has a smaller, easier to understand grid that is accurate to +/-1 m. All of K-Country is in Zone 11.
It all starts with the Zone
In the UTM system, you start with the Zone number. Then you a number for the distance in meters east of the western edge of your Zone (called the “easting”). Add a second number for how far north you are from the equator (called the “northing”). A full UTM looks like this:
- Zone XX (always a 2 digit number)
- Easting YYYYYY (always a 6 digit number)
- Northing ZZZZZZZZ (always a 7 digit number)
UTMs gives you a highly accurate location within 1 m. This is generally FAR more precise than you need. There are a lot of numbers, though – but it can be easily simplified, as we will show below.
Both Kananaskis Mountain Rescue and Kananaskis Emergency Services work almost entirely in UTM. If you call in a rescue, and give them a lat/long, they’ll convert it to UTM to find you. Here’s the handy calculator they use.
A real example
Want to see UTMs for real? Pull out your favourite Gem Trek map, or look at this picture of the top right corner of GemTrek’s “Canmore and Kananasksis Village” map, to see UTMs (and Lat Long) in action (Ed. note: thanks to GemTrek for giving us permission to use these map images).
See that blue grid? That’s the UTM grid, made up of 1 km squares. Another nice feature of the UTM grid is that it clearly shows 1 km distances, making it easy to estimate how far things are away.
By comparison, look at the inaccuracy of trying to figure out your lat/long, which are the black and white bars. No lines are on the map (they rarely even on a government topo map, and if they are, they’re not straight). Divisions on the side scales are 5’ of latitude. No way you could derive a lat/long and be even +/- 100m.
Take a look at the snapshot of the GemTrek map to the right to see the full corner of the map including Barrier Dam Day Use Area. It’s full UTM is
- Zone: 11
- Easting: 637626
- Northing: 5655145.
That UTM doesn’t look much simpler than lat/long. But there’s a super simple fix.
Making UTM even simpler
Let’s zoom in of the map to the Barrier Dam area with the top side and right side scales folded in. That’s the image below. Here you can see the advantage of UTM, because you can shorten the full UTM to just 6 digits and make it accurate to +/-100 m (good enough for most things). Barrier Dam is normally just called “Grid Reference 376551”. You can just use the middle 3 digits of the UTM Easting & Northing. The Easting of 637626 has the “376” pulled out of it, and the Northing of 5655145 has the “551” pulled out of it.
The numbers in blue on the top and bottom of the map are the 2nd and 3rd digits of the UTM (the 37 part). You can eyeball the 3rd number as being 6/10ths of the way between the 37 and 38 line. The blue numbers on the left and right of the map are the 4th and 5th digits (the 55 part). Again, eyeball 1/10th the way between the 55 and 56 lines. The intersection of those two points is where you are, +/-100 m. And on a Gem Trek map or any other topo map, that’s almost always accurate enough.
6 digit UTMs are commonly used
Gillean Daffern loves 6-digit grid references. There are hundreds of them in her indispensable Kananaskis Trail Guide Books. Many of her hikes lead to places like:
- “Ridge 413572” (east of Barrier Dam, north of Hwy 68);
- “Peak 238342” (an unnamed peak near Lillian Lake);
- “Pass 155226” (South Burstall Pass, actually).
So long as you stay in UTM Zone 11, her 6-digit reference is good enough to find yourself within 100 m or so, and do so within seconds on a Gem Trek map — almost.
Datums: A topic for another page
One of the minor problems of mapping is the underlaying survey datum used to make the map. Gem Trek uses something called NAD (North American Datum) 83. Gillean often switches between UTMs based on NAD 83 and UTMs based on NAD 27 (present on many government topo maps). Sigh. Still, the differences between NAD 83 and NAD 27 are only about 200 m. Maybe on another page, we’ll try to explain datums. Maybe.
Make your navigation and map reading easier
Grab a Gem Trek Map next time you’re heading off into K-Country. Find your starting point and figure out the 6-digit UTM at that point. Then do it again for where you’re going. Most GPS units and apps allow you to switch displays to UTM units. Do it. Discover for yourself how elegantly simple the UTM system is (despite our complicated explanation as to how they work!).