- May 19, 2023
I’ve been scratching my head trying to think of one special number that everyone understands and most riders agree captures in one number the “steepness” of a route so it can be compared with other routes measured the same way. Having a cutoff for steepness, the way I did it above, is easily understood but different cutoffs give different results. Also, if we say “steep” means over 15% grade, then a 14.9% grade counts for nothing and a 15.1% grade counts the same as a 35% grade. I think for reducing “the steepest road in Thailand” to one simple number which reflects (only) the steepness of the route that can be calculated from actual GPS tracks, we need a number that gives more weight to more time spent on steeper grades and more weight to steeper grades and does not require any arbitrary cutoff at all. How about the time-weighted slope of the route? The sum of the products of the time between each trackpoint and the grade of each trackpoint, divided by the moving time of the route. The number means the time-weighted average slope of the total route, in percent grade. It seems to work well. Big Dipper is still #1. What do you think?