Definition: Colour model
UN - Geographic Information Systems
A procedure for representing colours numerically in a computer. For example, in the RGB colour model, colours are represented as numeric levels of red, green and blue. Pure red, for instance, is defined as 255,0,0. Other examples of colour models are the hue, lightness, saturation (HLS) and cyan, magenta, yellow (CMY) models.
United Nations, "Handbook on Geospatial Infrastructure in Support of Census Activities", Department of Economic and Social Affairs, Statistics Division, Studies in Methods, Series F No. 103, New York, 2009