Device + Relative Elevation
The iPhone (maybe android) collects relative elevation from the barometer.
This can be merged with the device elevation (from the GPS) to compute a
smooth "corrected" stream.
Test activities: 339063817 407519242
Elevation Gains (ft)
Computed from the respective streams,
Corrected strong/weak is the elevation gain computed using the
X-axis is distance (miles), y axis is elevation (ft). Click and drag to zoom in.
Vertical and Horizontal GPS Errors