Korrelmaat

Korrelmaat is a Dutch term used to denote the characteristic length scale over which a property of a spatial field remains correlated. In physics, statistics and geostatistics it is commonly referred to as the correlation length or correlation length scale. It describes the distance at which the two-point correlation function has decayed to a small fraction of its value at zero lag, often chosen as 1/e, or as the integral scale defined by the area under the normalized correlation function. The korrelmaat thus characterizes the size of coherent structures in a field and is a key parameter in modeling spatial variability and in designing experiments or simulations.

In materials science and metallurgy, korrelmaat is sometimes used to denote grain size—the average linear dimension of grains in a polycrystalline material. Grain size affects mechanical properties and is typically measured by microscopy using standardized counting or intercept methods; reported values may include the mean grain diameter or equivalent diameters.

Estimation and interpretation: Korrelmaat is estimated from data via empirical autocorrelation functions, semivariograms, or spectral methods. Different conventions (e.g., 1/e decay, half-maximum, or integral length) may be used, so it is important to state the definition when reporting the value. In practice, the korrelmaat influences sampling density, numerical discretization in simulations, and uncertainty estimates in spatial predictions.

See also: correlation function, correlation length, semivariogram, grain size, intercept method.