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Format request: .fit

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
48/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Active
Tech stack
csharp
Domain
full-stack

Research direction

Read the repository’s existing format converter entry points and the project’s conversion tests to see how new formats are registered. The issue requests FIT input conversion to GPX, TCX, and CSV, with GeoJSON and KML as additional possibilities, but names no files or implementation path. Done means FIT activity data can be converted to the requested outputs and the conversions are covered by tests.

Written by the indexing model from the issue text.

Description

formats
File extension

.fit

What makes these files?

Garmin devices and apps (Garmin Connect, Forerunner, Fenix, Edge), and also Wahoo, Coros, Polar, Suunto and Strava exports. It is the standard binary format for recording sports activities (running, cycling, swimming, etc.).

What should Filee convert them to?

GPX, TCX, CSV (and ideally GeoJSON/KML)

Anything else?

FIT (Flexible and Interoperable Data Transfer) is a compact binary format created by Garmin. It is not encrypted or DRM-protected. The spec and SDK are public.

Use case: moving activities between platforms and tools that only accept GPX/TCX, or analyzing training data (pace, heart rate, cadence, power, elevation) in spreadsheets as CSV.

Related fitness formats that would be great to support as well (inputs and outputs):

  • .tcx (Training Center XML, also from Garmin)
  • .gpx (GPS Exchange Format)
  • .fit <-> .tcx <-> .gpx <-> .csv

Documentation: https://developer.garmin.com/fit/overview/
Open-source tools that read FIT: Garmin FIT SDK (official), fitparse and fitdecode (Python), GPSBabel.

Protection
  • These files aren't encrypted or copy-protected (DRM), and I can open them without a password.
Dominant language
C#
Stars
3.6k
Forks
192
Avg merge
5h 33m
Merged PRs (30d)
72

Getting set up

This project ships no dev container, Dockerfile or contributing guide, so setting up is up to you: start from its README, and see our first-contribution guide for the general steps.

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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