A scholarly resource must be written by a scholar - an expert in the field, usually with a PhD or equivalent qualifications. Scholarly resources usually tell you about the author, so that you can assess whether s/he is a reliable expert on the information presented.
Walkmeter uses GPS to measure the distance of your walks and hikes outdoors. It functions much like a stopwatch. Open the app, tap Start, and use Lap when you want to log an interval. It maps your walk, and you can view time, speed, distance, and pace as you walk.
Smartphones with Fitness Apps. Best for tracking speed, distance, elevation gain. There are numerous free apps available to download onto your smartphone that work with your phone's GPS to allow you to track your speed, distance, elevation gain and more while you run, bike or hike.