Linked from
The 18 pages that link to Interpolation, each with the reason it gives.
Calibration curveRelated: Unknowns within the standards' range are estimated from the fitted curve.
Slide ruleRelated: Fine results often depend on estimating positions between printed graduations.
Linear functionRelated: A line through data points supplies estimates between measured inputs.
Adaptive mesh refinementRelated: Values must be transferred between coarse and fine mesh levels.