Average Gradient? Pffffffft!
When climbing notable cols in the French Alps, there are kilometre markers along the road that provide bits of information, such as the name of the col (to reassure you whilst baking in the sun that you are still climbing the same bloody col you started climbing in the morning when it was still cold and misty), the current altitude (to let you know whether you have reached a point where you can use altitude sickness or oxygen depletion as an excuse to give up even though you know that getting anywhere near such an altitude is at the summit if at all), the remaining distance to the summit (almost always more than one would have guessed) and the gradient for the next kilometre. The last bit of data is a tricky one because it is the average gradient.
It is simply the arithmetic mean.
I actually do not remember whether it was on the way up Col de la Bonette or another col, but there was a marker that said 0% gradient. I thought, ‘Fantastic, just like Antwerp. A welcome little respite.’ Wrong!
The road took a sharp dip shortly thereafter. I knew that the short, acute descent was bad news… The remaining bit was an ascent of at least 8%, probably exceeding 10% at some points. I could literally see how the average turned out to be 0%, but it was an utterly useless piece of information. It would have been more helpful to know the range albeit, assuming a minimum gradient of -10% and a maximum gradient of 10%, a range of 20 would have provoked a few choice expletives.
In either case, it illustrates how you can allow numbers to control you rather than you taking control of a situation. It is the main reason why I have not been able to persuade myself to actually get a cycle computer (speed, altitude, heart rate, cadence, blah di blah) despite the convenience of having a gadget that tells me where to turn especially when out on an unfamiliar route. Still dithering…