How to tell how much of a hike was uphill, downhill or flat

The short answer

Elevation gain adds up every metre you climbed regardless of when in the walk it happened, so it cannot tell you whether that climbing was one long stretch at the start, several short pinches spread across the route, or a gradual grind the whole way. Working that out means returning to what a GPX track already records — a position, an elevation and a distance at every point — and comparing each point to the next rather than looking only at the total.

Walk through the recorded points in order. If the elevation rose by more than a small threshold, call that stretch climbing. If it dropped by more than the same threshold, call it descending. If it stayed within the threshold either way, call it flat. Add up the distance covered in each of the three groups and you have a rough uphill, downhill and flat split for the whole route — read from the shape underneath the total, not from the total itself.

Why a threshold, not just up or down

Comparing raw elevation point to point and asking only whether the next value is higher or lower falls apart on a genuinely flat trail. GPS altitude and barometric readings both carry a small amount of noise, so consecutive points on level ground still wander up and down by a metre or two even though the ground itself never moved. Classify every one of those wobbles as a climb or a descent and a flat fire road comes out looking like a staircase, flipping between uphill and downhill every few points.

The fix is the same one hiking apps already apply to elevation gain itself: ignore changes smaller than a small threshold, somewhere around a few metres, and only count a stretch as climbing or descending once the elevation has moved past it. Exactly where to set that threshold is a judgement call rather than a fixed rule, which is also why two people sorting the same file by hand can land on slightly different splits. The result is a rough shape, not a precise percentage.

The faster way: read the profile instead of the numbers

Working through a raw file point by point gets you an answer, but it is not the only way to one. An elevation profile — the line drawn under a map as a route replays, plotting height against distance covered — shows the same information visually, and a human eye is very good at sorting climbing, descending and level ground on sight without running any numbers at all. A steady rise reads as a line sloping up. A descent reads as one sloping down. A flat stretch reads as roughly level, wobble and all, in a way that is obvious to look at even though defining it precisely in code still needs that same threshold.

TrailCam draws that elevation profile under the map for every saved route and keeps it running underneath while you replay a hike, alongside the distance, moving time and pace for the walk as a whole, so the shape of a route is something to look at rather than something to work out by hand.

What the split is actually useful for

Two hikes with identical distance and identical total elevation gain can be very different afternoons depending on how that climbing is arranged. Six hundred metres of gain spread evenly across twelve mostly-flat kilometres, with the odd gentle rise, paces very differently from the same six hundred metres concentrated into one steep kilometre near the end, with everything else genuinely level. The total gain figure cannot tell those two routes apart; the shape underneath it can.

Knowing the split ahead of a hike, or reading it back afterward, is mostly about where to expect the effort to land, not about turning the walk into something to hit a target on. A route that is mostly flat with one short climb near the trailhead lets you settle into an easy rhythm early and save the effort for a known stretch, instead of pacing the whole thing as if the climb could arrive at any point.