I have the GPS tracks of a skier's morning activity where they have hiked up the mountain for the most part, and then skied down from the top afterwards. I am attempting to differentiate sections of the GPS track using a speed threshold. This threshold is to determine which sections of the GPS track consists of skiing and of walking. I want to be able to identify this so that I can calculate the skiing distance separately from the walking distance.
I have loaded the gpx file into R and managed to plot a simple line-route of the skiing activity. When I load the same file into Google Earth Pro, the elevation model tells me the speed at which the skier is travelling at in kmph. Therefore, I assume the speed is already included in the gpx dataset, though this is not present when I load the same gpx dataset into R. How do I calculate the speed at each data point of my GPS track and create a column for this data?
Once I have calculated the speed of each of these points, I then want to select all the data points which have a speed above a certain threshold. Of the selected points, I want to calculate the total distance travelled above the threshold speed. For example, the average speed of a skier is 10-20mph. Therefore, I would select all of the data points which have a speed above 10mph and then calculate the distance between each of these points. How can I do this?