Usually, interpolation is used to create approximately, a continuous variable from a discrete set of values from this variable (comité français de géographie), that is to say researching a function which goes through known points.
In geomatics, interpolation is used to create data for points in space which don’t have data, based on known points. However, there is an infinite number of possibilities for interpolation, so it’s necessary to make an hypothesis about how the phenomenon propagates in order to coherently select the interpolation method and its parameters.
A simple example of interpolation in geomatics is the establishment of a height layer from a discrete set of height points.Hereunder : three interpolation methods for the creation of a height layer from height points.
Source: Glossaire de cartographie, Comité français de cartographie, Bulletin N° 123-124, Mars-Juin 1990.