An outlier is an observation that “deviates so much from other observations as to arouse suspicions that it was generated by a different mechanism”—D. M. Hawkins, Identification of Outliers, vol. 11. London, UK: Chapman and Hall, 1980.
Peter, B. G. and Messina, J. P. 2019. Errors in time-series remote sensing and an open access application for detecting and visualizing spatial data outliers using Google Earth Engine. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 0(0):0–0. doi: 10.1109/JSTARS.2019.2901404