If you want to create your own heatmap – but lack a webserver – I’ve updated the script shared earlier to allow generating content to run on jsfiddle.
How to plot a heatmap of your Garmin tracks on Google Maps JS API:
#1 request all your data from Garmin: https://www.garmin.com/en-US/account/datamanagement/
#2 download https://github.com/musings-hub/garmin-fit-to-heatmap-js
#3 run it: python3 fit-to-js-threaded.py ./Garmin/fit/
This will generate a file named “heatmap-datapoints.js“.
#4 open heatmap-datapoints.js and copy the contents into jsfiddle (see screenshot above).
#5 update the javascript to include your own API key for Google Maps API (see https://developers.google.com/maps/documentation/javascript/get-api-key for how to get such a key if you don’t have one already).
#6 click “Run” in jsfiddle.
#7 admire the heatmap of your location based activities 😊