When you press the locate button on the map, Trackbash requests location data from your device. If possible, your device may return GPS data including altitude. If this does happen, then Trackbash attempts to create a track profile from the data.

As explained in the article linked below, GPS altitude data is very inaccurate and noisy. To try and get around this, we use a polynomial linear regression function to create the profile.

You can change the order of the polynomial function using the slider above. A higher number will more closely follow the data but will include more of the GPS errors and noise. A lower number will provide more smoothing but be less accurate. You can choose which you prefer. The R2 figure R2 is the the coefficient of determination which measures how closely the profile follows the data (from 0 to 1 where 1 is a perfect fit). However, a perfect fit to the data is NOT ideal (because we are trying to remove error and noise) - somewhere about .8 is probably a good target.

For more details see : Article : GPS to Gradient Profile