GPX course analyzer

Drop a race's GPX and see the course the way Pendio reads it: the elevation profile, D+ and D−, the hardest climb and descent, how the climbing is spread over the distance and how much of it is steep. Free, no account, and the file never leaves your browser.

Elevation · Three Passes 50 peak 2,645 m
0 km50.3 km
Hardest climb11.0 km @ +12.2 %
Hardest descent9.5 km @ −16.2 %
Distance
50.3 km
Gain
↑ 2,757 m
Loss
↓ 2,757 m
Peak
2,645 m

Flat-equivalent distance

67.8 km for 50.3 km on the map

The flat distance that takes as long as this course at the same effort, by the grade-adjusted pace model Pendio's race plans use.

Terrain

Climbing 47 %Flat 6 %Descending 47 %

Distance in each grade band
GradeDistanceShare
≤ −20 %3.1 km6.1 %
−20 / −15 %4.8 km9.6 %
−15 / −10 %5.3 km10.6 %
−10 / −6 %3.4 km6.8 %
−6 / −3 %3.7 km7.4 %
−3 / −1 %3.1 km6.2 %
−1 / +1 %2.9 km5.8 %
+1 / +3 %2.5 km4.9 %
+3 / +6 %3.3 km6.5 %
+6 / +10 %4.3 km8.5 %
+10 / +15 %6.8 km13.6 %
+15 / +20 %4.7 km9.3 %
> +20 %2.3 km4.5 %

D+ per 10 km

0–10 km807 m
10–20 km619 m
20–30 km745 m
30–40 km577 m
40–50 km71 m
50–50.3 km0 m

Biggest climbs

From (km)Length (km)D+ (m)AverageSteepest 100 m
3.511.01,341+12.2 %+22.9 %
23.93.4561+16.4 %+27.4 %
33.13.1444+14.2 %+23.7 %

Biggest descents

From (km)Length (km)D− (m)AverageSteepest 100 m
36.39.51,540−16.2 %−28.8 %
14.76.2831−13.4 %−22.3 %
29.60.865−7.8 %−14.5 %

What it shows

Distance, D+ and D−
The course's length and its total climbing and descending.
Hardest climb and descent
The stretch with the highest average gradient × length, uphill and downhill, marked on the profile. Drag across the profile to read the distance, altitude and gradient anywhere.
Flat-equivalent distance
How long the course is in flat kilometres of the same effort (see the questions below).
Terrain
How much of the distance climbs (steeper than +1 %), runs flat and descends (steeper than −1 %), and the distance in each of 13 grade bands, from −20 % and steeper to more than +20 %.
D+ per 10 km
The climbing in each 10 km of the course, the biggest slice highlighted: where the race front-loads its vertical, or saves it for the end.
Biggest climbs and descents
Up to five of each: where they start, how long and how high they are, their average gradient and their steepest 100 m.

How it reads the GPX

The course is resampled every 10 m and its elevation smoothed over 70 m, so GPS and barometer noise don't add phantom climbing; D+, D−, the gradients and the grade bands come from that smoothed line. A climb is a stretch steeper than +2 % (a descent, steeper than −2 %); a flatter break shorter than 150 m doesn't split it, and it counts once it is 200 m long or 12 m high. D+ per 10 km is counted on the recorded elevation, ignoring rises under 3 m, so its slices can add up to a little more than the D+ above.

It's the analysis the Pendio app runs on a race course, ported to run in the browser and checked against the app's own results, so the numbers here are the ones you'd see in Pendio.

Questions

Is my GPX uploaded?

No. The file is read by this page's script in your browser and never leaves it: not the track, not its name. Reload the page and it's gone.

Why is the D+ different from my watch or another app?

Every tool treats elevation differently: some count every small bump of GPS or barometer noise, others smooth it away. This page resamples the course every 10 m and smooths the elevation over 70 m before adding up D+ and D−, the same method the Pendio app and pendio.app/app use, so a course reads the same everywhere in Pendio.

Which files work?

A .gpx file up to 25 MB with elevation in it. Pendio reads its track points, or its route points if it has no track. Most race websites and route planners can export one.

What does the flat-equivalent distance mean?

The flat distance that would take as long as this course at the same effort. Every 10 m counts more or less than its length depending on its gradient: climbs count for more, downhills down to about −16 % for less (least around −8 %), and steeper downhills for more again. It's the model Pendio's race plans use to share a target time out between the legs.

Can I plan the race from here?

In Pendio, yes. Sign in at pendio.app/app to keep the course, set a target time and build the aid-station splits, the fueling plan and a printable pace card. The iPhone app, in private beta, adds the analysis of your training.