Parses the trackpoints of a .tcx workout (the common Garmin Connect / Strava
export) into a tidy data frame: time, position, altitude, distance, heart rate
and cadence/speed where present.
Value
A data frame of trackpoints (time, lat, lon, altitude_m,
distance_m, hr, cadence, speed), time-ordered, with the activity
sport in attr(, "sport").
Examples
if (FALSE) { # \dontrun{
tp <- readTCX("run.tcx")
plot(tp$lon, tp$lat) # the route
} # }