trailphysics

How long a ride, hike or run really takes.

Route geometry and pace physics for JavaScript and Swift, open source and held to the same numbers by 242 shared test vectors. Move the sliders: every figure below is computed live by the library.

npmnpm install trailphysics SwiftPM.package(url: "https://github.com/ehilzinger/trailphysics-swift", from: "0.1.3")

Hover the chart for exact values

Rider

Bike and kit

Power at the pedals

Bike

Surface

Dashed: a loaded tourer, 75 + 25 kg at 180 W, for comparison.

On the flat–

Up 8%–

10 km at 7%–

Drag area (CdA)–

Speed against gradient, km/hYour riderLoaded tourer

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Below −2% the model has the rider freewheel, which is the step in the curve. Descents are capped at 65 km/h.

The same call in your code

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Two ports, one set of numbers

The JavaScript package writes the test vectors; the Swift package reads byte-identical copies, and both suites check every one. A phone and a browser give the same person the same time for the same route. How the vectors work.

242shared vectors

0.01 stolerance on times

10⁻⁶on everything else