FIT File Merger

Purpose

The FIT File Merger is a tool designed to merge multiple FIT files recorded into a single file. This is particularly useful for athletes and fitness enthusiasts who use multiple devices to track their activities and want to consolidate their data.

FIT File Merger is intended to merge data recorded on multiple devices at the same time during the same activity into a single file. It is not intended to chain subsequent activities together.

Currently supported functionality

Merge Power data from separate fit file into a main fit file.

This is useful when you have no connection from your powermeter, home trainer, or an app to your cycling computer. Using FIT File Merger, you can merge the separately recorded power data into the fit file recorded by your bike computer without losing any data. This includes calculations of average and max values for each lap as well as for the total session.

Usage

fitfilemerger.exe path\to\main.fit path\to\secondary.fit path\to\merged.fit 

Setup in VSCode

1. Create a .NET Solution

   dotnet new sln

2. Clone the Repository into your workspace

   git clone https://github.com/joc59/fitfilemerger.git

3. Add fitfilemerger to your solution

   dotnet sln add fitfilemerger\fitfilemerger.csproj

4. Build fitfilemerger

   dotnet build

5. Publish fitfilemerger

   dotnet publish

Debugging

The files in examples can be used for testing and debugging purposes. The garmin- files are meant to be the main files, while the elite- files contain power values and are meant to be the secondary files. As a result, the power values from the elite- will be merged into the garmin- file.

1. Add the following to your launch.json:

   "version": "0.2.0",
   "configurations": [{
      "name": ".NET Core Launch (console)",
      "type": "coreclr",
      "request": "launch",
      "preLaunchTask": "build",
      "program": "${workspaceFolder}/fitfilemerger/bin/Debug/net8.0/fitfilemerger.dll",
      "args": [
          "examples/garmin-2025-01-17.fit",
          "examples/elite-2025-01-17.fit",
          "examples/merged-2025-01-17.fit"
      ],
      "cwd": "${workspaceFolder}/fitfilemerger",
      "justMyCode": true,
      "stopAtEntry": false,
      "console": "internalConsole"
   }]

2. Add the following to your tasks.json:

   "version": "2.0.0",
   "tasks": [
      {
          "label": "build",
          "command": "dotnet",
          "type": "process",
          "args": [
              "build",
              "${workspaceFolder}"
          ],
          "problemMatcher": "$msCompile"
      }
   ]

Contributing

Pull requests are welcome!

License

Distributed under the Unlicense License. See LICENSE.txt for more information.

FIT File Merger requires the Garmin FIT File SDK, which is published by Garmin under a different license. Garmin FIT File SDK is not included in this repository but will be installed through your package manager upon build.