Another Way to Find Yourself

Fourth article in a seven-part series

In Canada, 1:50,000-scale topographic maps are printed with the 1,000-meter UTM grid in place, while USGS topo maps show grid designations as tick marks along the margins. Most experts suggest drawing some or all of the grid lines on new USGS topo maps with a waterproof ink to make measurements easier.

A Canadian 1:50,000 topo map showing the UTM grid with easting and northing notations (above).

A USGS 7.5-minute map with blue UTM ticks and notations (below).

I find it helps to write UTM locations like this:

(06) 42.850 E
(51) 27.650 N

To find the location on my map I'll start at the lower left corner and work eastward along the margin until I find UTM grid line 42. My actual location line can be easily estimated or accurately measured as 0.8 or even 0.85 farther east within the 1,000-meter square. I draw a vertical line from that point.

Similarly, I'll follow the grid numbers north from the same corner to line 27 and then estimate or measure 0.65 (0.6 is accurate enough for most bushwhacking) farther north and draw a horizontal line to intersect with my vertical easting line and—voila!—there I am!

Keep your location lines parallel with the UTM grid lines. The grid is aligned with its own north, called "Grid North."

With UTM it's easy to measure a location on a map and enter the coordinates into a GPS for navigation. I usually only worry about one decimal place accuracy for most navigation, and I"zero" the last two places in my GPS entry, since the software demands something in those spaces.

Even if you're a "dyed-in-the-wool" latitude/longitude aficionado, give UTM a try. It's an easy and quick way to record and communicate waypoints.