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If you're preparing for a hike or any outdoor expedition, mastering UTM coordinates is key. The Universal Transverse Mercator system provides a grid-based method to pinpoint locations on a map. This system is commonly used by GPS devices and physical maps, including those in travel guides. In this guide, we'll teach you how to find and read UTM coordinates, so you'll always know your position, wherever you may be.
Instructions
Identify the UTM zone you're in.
The globe is split into 60 distinct UTM zones.
Choose the correct datum for your coordinates.
- The most frequently used reference datums in North America include NAD 27 CONUS and WGS 84.
- Here's how reference datums work: the datum is the point from which all measurements on the map are taken. Choosing a different point of reference can drastically alter the coordinates. If your GPS and map use different datums, you could end up in the wrong location.
Identify the easting value.
The first number in UTM coordinates represents the easting.
- The easting indicates how far east you are.
- If using a map, check the numbers along the map's edges that correspond with the UTM coordinates. The easting values will be located at the top and bottom of the map.
- When using a GPS, the easting will be the first number displayed when in UTM mode.
- A change of just 1 unit in easting (for example, from 510,000 mE to 510,001 mE) equals a shift of approximately 1 meter (or 1 yard) on the ground. Moving from 510,000 mE to 511,000 mE while keeping your northing constant will mean you've traveled about 1 kilometer (or 0.62 miles).
- You can estimate the exact location by interpolating the easting coordinates on the grid.
Determine the northing value.
The second number in UTM coordinates represents the northing.
- The northing indicates how far north you are.
- If you're using a map, check the numbers along the edges of the map that correspond to the UTM coordinates. You'll find the northing values along the right and left sides of the map.
- In UTM mode on a GPS, the second number you see is the northing.
- A change of 1 unit in the northing (for example, from 510,000 mN to 510,001 mN) reflects a shift of about 1 meter (or 1 yard) on the ground. Moving from 850,000 mN to 851,000 mN while keeping your easting fixed will mean you've walked roughly 1 kilometer (or 0.62 miles).
- To determine your precise location, interpolate the northing coordinates on a grid.
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A plastic UTM grid reader can be used alongside a map for highly accurate interpolation of UTM coordinates. However, make sure the scale of your UTM tool matches the map scale, as mismatched scales between the tool and map can lead to inaccurate coordinates and plotting errors.
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One common issue when using UTM coordinates is mismatched datums. If you're encountering problems, your first step should be to verify that all your maps, books, and GPS devices are set to the same UTM datum.
