  The problem of determining total distance ascended during a mountain bike
trip is addressed. Altitude measurements are obtained from GPS receivers
utilizing both GPS-based and barometric altitude data, with data averaging used
to reduce fluctuations. The estimation process is sensitive to the degree of
averaging, and is related to the well-known question of determining coastline
length. Barometric-based measurements prove more reliable, due to their
insensitivity to GPS altitude fluctuations.
