What is kriging?

“Geostatistics” is the generic name for a family of techniques which which are used for mapping of surfaces from limited sample data and the estimation of values at unsampled locations. First developed 40 years ago by Georges Matheron (above left) and named in honour of Danie Krige (right), these methods are now widely used in the minerals industry and have disseminated out into many other fields where 'spatial' data is studied.

Geostatistical estimation is a two stage process:

i. studying the gathered data to establish the predictability of values from place to place in the study area; this study results in a graph known as a semi-variogram which models the difference between a value at one location and the value at another location according to the distance and direction between them;

ii. estimating values at those locations which have not been sampled. This process is known as ‘kriging’. The basic technique “ordinary kriging” uses a weighted average of neighbouring samples to estimate the ‘unknown’ value at a given location. Weights are optimized using the semi-variogram model, the location of the samples and all the relevant inter-relationships between known and unknown values. The technique also provides a “standard error” which may be used to quantify confidence levels.

In mining, geostatistics is extensively used in the field of mineral resource and reserve valuation - the estimation of grades and other parameters from a relatively small set of borehole or other samples. Geostatistics is now widely used in many other fields. Obviously there are geological and geographical applications. However, the techniques are also used in such diverse fields as hydrology, ground water and air pollution, soil science and agriculture, forestry, epidemiology, management of wildlife and weather prediction.

In recent courses, we have provided training for participants working in: mining, geology, exploration, fisheries, agriculture (pests, fertilisers and yields), seabird preservation, urban air pollution, radioactivity monitoring, groundwater pollution, wildlife conservation………….

A longer explanation(!) can be found in an early publication of mine
(Royal School of Mines, 1978! Look how young I was…………………..)