This is awesome.
My dog does this, too. Especially when we hike with other dogs—or snowshoe, as I did this winter, once—he runs a mile for every one of mine.
App used below:
“Strava. It’s got the data cyclists crave.” Also: “My Tracks” by Google is free, synchs to Google Drive, easily shareable, and packed with stats. And viewable on Google Earth.