Originally Posted by
Iride01
The weather here has been pretty stable. No fronts of areas of high and low pressure moving through. Just sometimes rain and a thunderstorm that develop and dissipate in pretty much the same general area. So my last 5 rides over 2 hours had a start finish difference averaging 48 feet. The biggest 62 feet and the smallest 38 feet. Not a lot. However some where back in my history I've seen on the order of 100 feet of change or more during a ride.
2 hours is about 30 miles. I suspect the percent of error is larger for for smaller elevation gains (let's say < 1000 feet) than it is for larger numbers. a 100 foot difference is only 10% of 1000 feet. I wonder what you get for gain and loss.
There also isn't a "right" elevation gain number. It has to smooth the data (otherwise, it would count every little jiggle).
Originally Posted by
Iride01
I'm not suggesting this is the reason for the OP. But this and other things can add up to always make the relative or actual elevation numbers be different from one ride to the next.
The OP's numbers are on the low side. And, except for two outliers, the numbers are pretty close. Is a 50 foot difference even meaningful?
Since elevation gain is not considering grade at all, it's a weak indicator of effort anyway.
Originally Posted by
Iride01
For me, elevation gain/loss is a lot like Calories. The actual exact number is not important. If someone wants to ride hilly terrain, then ride the routes that show the most gain loss per distance. Doesn't matter if they don't match up from day to day.
Map data isn't correct for total elevation gain, nor are our barometric sensors in our devices and certainly GPS calculate altitude is less trustworthy. So people need to learn to judge by the trends and not the actual exact number they will never have.
Yes. Some people appear to expect the same level of accuracy for elevation gain as for horizontal distance. That doesn't seem realistic.