---
tag: 0Q4CJ5NAT1
kind: concept
name: Arc length parametrisation
aliases: [natural-parametrisation, unit-speed-parametrisation]
msc: [53A04]
uses: [0V7090SSPC, 0HATW2VWAZ]
sources:
  - url: https://en.wikipedia.org/wiki/Differentiable_curve
    locator: Length and natural parametrization
---

## Summary

An arc length parametrisation of a [[regular curve|0V7090SSPC]] uses the distance travelled along the curve as the parameter.
In this parametrisation the curve has speed $1$ at each point.