Frequently Asked Questions (FAQ)

Below are the following FAQs:

1. What is a FIT file?
2. Why isn't there altitude/elevation data in my FIT file?
3. Which Devices and Sensors has php-FIT-File-Analysis been tested with?
4. Where are my FIT files?
5. Why aren't all Messages and Fields identified in 'profile.xls' (from the FIT SDK) included?

###1. What is a FIT file? FIT or Flexible and Interoperable Data Transfer is a file format used for GPS tracks and routes. It is used by newer Garmin fitness GPS devices, including the Edge and Forerunner series, which are popular with cyclists and runners.

The FIT format is similar to Garmin's Training Center XML (.TCX) file format, which extends the GPS Exchange Format (.GPX). It enables sensor data (such as heart rate, cadence, and power) to be captured along with GPS location and time information; as well as providing summary information for an activity and its related sessions and laps.

FIT files are binary-encoded rather than being bloated XML-like ASCII documents. This means that they have a much smaller file size, but are not human-readable with a text editor such as Notepad. For example, a FIT file of 250Kb may have an equivalent TCX file of approximately 5Mb. This enables them to be uploaded to websites such as Garmin Connect, Strava, MapMyRide, Runkeeper, etc relatively quickly.

###2. Why isn't there altitude/elevation data in my FIT file? Not all devices record altitude/elevation data, so it may not be present in a FIT file.

For example, Garmin's Forerunner 10 and 15 GPS watches do not record or display elevation. Instead, when an activity is uploaded to Garmin Connect, altitude/elevation data is looked-up for each GPS position in the file and an elevation profile is generated. To mimic this behaviour Google's Elevation API can be used to achieve the same effect.

To check whether altitude/elevation data is contained in a FIT file, you can use the phpFITFileReader's show_debug() function and see which fields are present in record messages.

###3. Which Devices and Sensors has php-FIT-File-Analysis been tested with? Devices

• Garmin Edge 500
• Garmin Fenix 2
• Garmin Forerunner 110
• Garmin Forerunner 310XT
• Garmin Forerunner 910XT

Sensors

• Garmin Cadence and Speed
• Garmin Foot Pod (cadence)
• Garmin Heart Rate Strap (soft material version)
• Stages Power Meter If you have a different device or sensor and would like to submit a file for testing, please get in touch or create an issue on the GitHub project page!

###4. Where are my FIT files? You may find your FIT files in one of two locations:

• On the GPS device in the folder Garmin > Activities (plug it into your computer using a USB cable).
• C:\ drive > Users > Username > Application Data > Garmin > Devices > Device Number > Activities.

###5. Why aren't all Messages and Fields identified in 'profile.xls' (from the FIT SDK) included? After analysing FIT files from various Garmin devices, only the FIT Messages and Fields that have actually been observed (and thought to be most useful) have been defined within $data_mesg_info[]. Messages not defined within $data_mesg_info[] are dropped silently and should not create an error, however they will not be available in data_mesgs[]. If there are Messages and/or Fields, which would be useful to include in the class, then they can be added in a future release.