Originally Posted by
RChung
That's a different problem. Are you saying that if I hold my hand above a table top, there is no "right" distance between my hand and the table top? You can't measure a distance between two points unless they're connected? How about distance in the vacuum of space? In fact, the meter is defined as 1/299792458 of the distance light travels in a vacuum in one second, so we can certainly measure a distance in a vacuum.
There is a distance, and there is a measurement of that distance.
The accumulated elevation gain is the problem of interest to cyclists, and it’s analogous to the “length of a coastline” problem.
Of course, it’s simple to determine the elevation difference between two points. But the accumulated elevation gain between two points is path dependent. And you will get a different result if you use a different length ruler.