Handling of very steep profiles

[LDWhite68]

It seems there is a small bug (or possibly intentional limit) in the profile gradient calculation. If I digitize a gpx track segment that is very steep, the Profile info gets messed up. For example, I did a test segment with just two points that shows a climb of 221 ft in a distance of 204 ft. Yet the digital readout says a Grade of 0%. In reality it should be over 100% (i.e. more than a 45 degree angle). If I switch the y axis to Grade, then the y axis is scaled from 0% to 14000%, and the x axis shows 0.0 on both ends. In a similar test with a rise of 240 ft over a distance of 294 ft, the correct grade is calculated of 81.7%. But setting the y axis to Grade still produces the obscene graph scaling.

[ScottMorris]

I believe there is some (not well documented) code that limits the grade -- it was put in to keep things reasonable due to general lack of accuracy in GPS elevation calculations.  But, it can be done better, or be set as an option.  I'll see what I can do.

[margaretfit]

If I switch the y axis to Grade, then the y axis is scaled from 0% to 14000%, and the x axis shows 0.0 on both ends. In a similar test with a rise of 240 ft over a distance of 294 ft, the correct grade is calculated of 81.7%. But setting the y axis to Grade still produces the obscene graph scaling.

This is something happening with me as well.


Proffessor Margaret Fitzgerald