Does hiking distance include the elevation you climbed?

The short answer

Every recorded point on a hike carries a latitude, a longitude and an altitude. Distance is worked out from the first two — it is the sum of the horizontal separation between one point and the next, added up over the whole route. Altitude never enters that sum. Elevation gain is worked out from the third value alone, comparing each point's altitude to the one before it and adding up the upward differences. The two numbers are calculated from different columns of the same table and never combined into one figure.

Why distance is measured flat rather than along the slope

Strictly speaking, the actual distance your boots cover walking up an incline is slightly longer than the flat-map distance between the same two points — the incline is the hypotenuse of a triangle, and a hypotenuse is always a little longer than the base underneath it. At the grades most trails actually have, that extra length is tiny. A steady ten per cent grade, which already feels like real climbing underfoot, only stretches the true walking distance a couple of per cent beyond the flat measurement. Consumer trail-recording software, TrailCam included, reports the flat distance rather than trying to account for that sliver, because the difference is small at ordinary hiking grades and because a horizontal distance calculated from GPS coordinates is the same convention used across GPX-based trackers, which is what makes a route recorded on one app readable and comparable on another.

Why the two numbers are kept apart on purpose

Folding climbing into distance would make the mileage figure depend on the shape of the terrain instead of on where you actually went — the same two-mile out-and-back would report a different length depending on whether it climbed a ridge or stayed level, which breaks the one thing a distance figure is supposed to be reliable for: comparing one route to another. Keeping the numbers separate means a five-mile flat walk and a five-mile walk with real climbing in it are recognisably the same distance, and whatever made the second one harder shows up honestly in the elevation gain figure instead of being quietly smuggled into the mileage.

It also means the two numbers can be read together rather than one standing in for the other — distance says how far, elevation gain says how much climbing was involved in covering it, and a grade calculated from the two together says how steep that climbing actually was.

What this looks like on an actual steep trail

A punishing climb and a gentle one covering identical GPS coordinates report identical distances, because distance was never reading the slope in the first place. What changes between the two is the elevation gain figure and, if you work it out, the average grade — both of which come from the altitude column that distance ignores entirely. A hike that feels much harder than its mileage suggests is not a sign the distance is wrong; it is a sign that most of the difficulty is sitting in the elevation number rather than the length of the line on the map.

Things that trip people up

• Expecting a steep hike to measure longer in miles or kilometres than a flat one covering the same coordinates — it will not, because distance is horizontal by convention and never reads altitude.
• Assuming a missing or oddly low distance means elevation was accidentally left out of the calculation — the two figures were never combined, so there is nothing to leave out.
• Comparing the mileage of a flat local walk against a mountain trail and concluding the mountain trail was "not that far" — the missing part of that comparison is the elevation gain figure sitting right next to it, not a fault in either number.
• Trying to judge how strenuous a hike was from distance alone — grade, worked out from distance and elevation gain together, is the number that actually reflects how steep the ground was.

Where TrailCam fits in

TrailCam records latitude, longitude and elevation for every point on a route, and reports distance, elevation gain, moving time and pace as separate figures rather than folding one into another — so a steep climb shows up honestly in the elevation profile underneath your replayed route, without quietly inflating the mileage next to it. TrailCam is free to download.