IUPAC definition : Continuous or repeated observation, measurement, and evaluation of health and/or environmental
or technical data for defined purposes, according to prearranged schedules in space
and time, using comparable methods for sensing and data collection.;
Continuous or repeated observation, measurement, and evaluation of health and/or environmental
or technical data for defined purposes, according to prearranged schedules in space
and time, using comparable methods for sensing and data collection.