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An Earth-centred orbit at relatively low altitude, commonly within roughly 2000 km of the surface. It supports frequent orbital revolutions and relatively fine spatial sampling for remote sensing.

An orbit passing near both geographic poles of its central body. Planetary rotation brings different longitudes beneath successive passes, useful for global remote sensing; one satellite still samples each location intermittently.

An operational spectral region often taken as about 1–2.5 micrometres in remote sensing, with convention-dependent boundaries. Water absorption makes suitable bands sensitive to leaf and surface moisture.

Assignment of observations to categories using measured features and a statistical rule. In geological remote sensing, features can be multispectral pixel values or derived spectral reflectance ratios; known field samples provide training labels and independent observations assess errors. Classification boundaries need not coincide with lithological contacts when illumination or cover dominates the signal.