How can I combine Garmin recorded track data with FitBit heart rate data?

Question

I have a Garmin Oregon 600 and FitBit Charge HR. Is there a way I can combine the GPS track from the Garmin with the heart rate data from the FitBit so that I can use it in a visualization tool like MyGPSFiles?

Also, if there is a way to do this by manually editing the files please let me know. I could turn this into a project and write a program to merge the data but I don't know what filetype would support this combination of data.

I would prefer not having to carry my cellphone, but would replacing the Garmin with a smartphone make it easier?

Answer 1

The GPX files produced by GPS devices are just XML so can fairly easily be edited by computer programs (and simple edits like removing sections where your GPS glitched out can even be done “by hand” with a text editor). The XML schema includes fields for all kinds of things, including heart rate.

It seems the FitBit Charge can export data in CSV format, which is also a simple-to-parse text format. Combining these with a script should be fairly easy as long as you know how to program and you use appropriate libraries for, e.g., handling the XML.

Make sure the clocks on your devices are well synchronised. A few seconds’ difference wouldn’t be the end of the world but you wouldn’t want more than that, I’d have thought.

Answer 2

As far as I can tell, this isn't possible to do at your end. I've got a Fitbit Surge, and although it is possible to export TCX files via the Fitbit website, the resulting file is useless (I'll paste in the complete file from a recent hour-long bike ride below). The Surge does have GPS built-in, and I suspect that if I turned on its GPS for a bike ride (at the cost of drastically shortened battery life), the file would be useful, but then there wouldn't be much need to combine that with another GPX file. Fitbit doesn't make it easy to play with other devices.

It's frustrating, but I think the right thing to do is to get a HRM that communicates with your Garmin over ANT+ (which most HRMs do, and which your Garmin supports). Or connect up to Strava, which seems like a viable option.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<TrainingCenterDatabase xmlns="http://www.garmin.com/xmlschemas/TrainingCenterDatabase/v2">
    <Activities>
        <Activity Sport="Other">
            <Id>2018-08-27T12:06:50.000-05:00</Id>
            <Creator xsi:type="Device_t" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
                <Name>Fitbit Surge</Name>
                <UnitId>0</UnitId>
                <ProductID>0</ProductID>
            </Creator>
        </Activity>
    </Activities>
</TrainingCenterDatabase>