Semivariance

Semivariance can be described by

$\gamma (h)=\sum _{i=1}^{n}(h){\frac {(z(x+h)-z(x))^{2}}{n(h)}}$

Where z denotes a data value at a particular location, h is the distance between data values, and n(h) are the number of pairs of data values a distance of h apart.

A plot of the semivariance versus distance between data values is known as a semivariogram, or simply as a variogram.

Relevant topics: geostatistics

References:

1. Shine, J.A., Wakefield, G.I.: A comparison of supervised imagery classification using analyst-chosen and geostatistically-chosen training sets, 1999, http://www.geovista.psu.edu/sites/geocomp99/Gc99/044/gc_044.htm