I'm guessing that when the track shows you going in repeated circles - around 20 in a row between 15 and 20k - you are actually spirally upward.
Right. Circling almost always means I'm in lift, except for some rare situations when I need to get down for some reason and do circles in sink (I can only remember having to do that once, because I was really high and was getting too cold). The spiral you pointed out was the best climb of the day; for a good chunk of that I was climbing at 350 feet per minute. Sometimes there are circles in lift that really just constitute wishful thinking, though. The three circles on my first flight were in this category; milkweed seeds would have been rising there, but I was just sinking more slowly than I would in still air, and still losing altitude. In open territory like this, figure-8s or zigzags mean I'm bleeding off altitude preparing to land, but near a ridge, it would mean I was in lift but didn't have enough separation from the terrain to do complete circles. Straight line flying means I'm going somewhere, probably somewhere I'm hoping/expecting to find lift (like under a cloud). And wandering means I kind of think there's lift around here someplace, but it's elusive.