metrictrails - Processing of GNSS Streams from Sports Watches

Tools to read, clean and standardise GNSS (Global Navigation Satellite System) streams recorded by sports watches and similar devices, with a focus on trail and mountain running. The pipeline reads GPX files, applies a naming convention, sanitises coordinates (Kalman, LOESS, Gaussian kernel or Savitzky-Golay smoothing, and red flags for implausible readings), resamples the trajectory to a uniform spatial resolution derived from the Nyquist criterion, and replaces elevation with values from a Digital Elevation Model. Derived measures include speed, slope, elevation gain and kilometre-effort, Tobler hiking function parameters fitted by quantile regression, comparison between streams, detection of passes along a route and map matching to a known reference trail by dynamic programming. Methods follow Sanchez and Villena (2020) <doi:10.1177/1754337120918975>, Sanchez et al. (2024) <doi:10.1109/ICECET61485.2024.10698606>, Sanchez et al. (2025) <doi:10.1177/17543371251341660> and Martinez, Sanchez and Diaz (2026) <doi:10.1109/ICECET65726.2026.11632531>.