Therefore, a stochastic simulation map represents the spatial distribution of the attribute more realistically than a smoothed kriged map.
The local standard deviation associated with kriged estimates varies much less across the study area (Fig.
With regard to estimation uncertainty, the map of standard deviations associated with the kriged estimates indicates that kriging standard deviation depends mainly on data configuration and therefore cannot be used as a reliable measure to report estimation precision.
The kriged variance violates the requirement of independence because the value of a kriged data point, once its position amongst a set of measured data points is selected, is determined by the set, and thus the dependent variable of a function.
Covariances and kriged variances dominate geostatistical theory.
Despite such valid concerns, concerns that most geologists and mining engineers share, kriging and kriged variances remain the geostatistical tools of choice, a fact to which numerous papers that extol the perceived power of kriging and the alleged benefits of software that fabricate kriged variances testify.
For example, M Armstrong and N Champigny, in "A Study on Kriging Small Blocks" (CIM Bulletin, March 1989), display smooth plots of kriged variances plunging to zero in chaotic domains (see also Figure 1).
The author shows how to predict recoveries and grades by entering differences between estimated variances and kriged variances into smoothing relationships that KRIVAR and DIDACTIC programs so conveniently provide.
Kriged variances violate the requirement of independence because the value of a kriged data point, once its position amongst a set of measured data points is selected, is determined by the set, and thus a dependent variable of a function.
Smooth plots of kriged variances in chaotic domains suggest geostatisticians found a way to beat divine powers at playing dice but they rigged the rules of the game.
Its practitioners should recognise that the kriged variance violates a fundamental principle.