The line is OpenStreetMap's mapping of the route (© OpenStreetMap contributors, ODbL), via Waymarked Trails, with heights from a 30 m terrain model. Check the current official route before a long trip: diversions and permitted paths change. See the source.
Start and finish
Start: 63.99061, -19.06158
Finish: 63.68430, -19.51238
Paths change, and the weather decides the day. The line comes from the source named under the map and the heights from a terrain model, so treat the figures as a guide. Check for diversions before you go, take a map, check the forecast, and turn back if it isn't right.