Glossary for Geospatial Science

HIS:Hue, Intensity, and Saturation.  Sometimes called HLS, for Hue, Luminance and Saturation.  The system of defining video output color from hue, intensity and saturation characteristics.  HIS controls are commonly used with color television sets.  Most computer displays use RGB (red/green/blue) color mixing information instead.

The hue-intensity-saturation color model uses a double cone (with its greatest circumference at the midpoint of the z-axis) to describe specific colors.  On any horizontal slice of the cone, the hue varies as you move around the slice and the saturation increases as you move outward from the center.  Intensity is the z-axis of the model.  The shades of gray are found along the z-axis, where hue and saturation equal zero.  (See also: HBS, RGB.)