I had my GPS with me on the hike. The main purpose is to have it constantly record location data so that I can merge that w/my photos later on. I have software that looks at the date/time stamp of each photo, then looks at the GPS log and writes the lat/lon & elevation data into the photo. Below is a graph of our hike. The GPS lost track of satellites during the last 500 feet of our final climb so the graph is truncated early.