We constraint on computer the best linear unbiased generalized statistics of
random field for the best linear unbiased generalized statistics of an unknown
constant mean of random field and derive the numerical generalized
least-squares estimator of an unknown constant mean of random field. We derive
the third constraint of spatial statistics and show that the classic
generalized least-squares estimator of an unknown constant mean of the field is
only an asymptotic disjunction of the numerical one.