Without diving in too deeply, it looks like they use a package called `gpxgo` [1], which has some code for calculating the moving distance of a given GPX file [

Without diving in too deeply, it looks like they use a package called `gpxgo` [1], which has some code for calculating the moving distance of a given GPX file [2]. [1] https://github.com/tkrajina/gpxgo https://github.com/tkrajina/gpxgo [2] https://github.com/tkrajina/gpxgo/blob/5e7c336e94dac3583a07c87dc77dd59acaa7be63/gpx/gpx.go#L1156-L1207 https://github.com/tkrajina/gpxgo/blob/5e7c336e94dac3583a07c...