Block correlation and the spatial resolution of soil property maps made by kriging

Using the block correlation and concordance correlation it is shown that the uncertainty of block kriged predictions depends on block size, but this effect depends on the interaction of the autocorrelation of the random variable and the sampling intensity. In some circumstances (where the dominant component of variation is at a long range relative to sample spacing) the block correlation and concordance correlation are insensitive to block size, but if the grid spacing is closer to the range of correlation of a significant component then block size can have a substantial effect on block correlation. It is proposed that (i) block concordance correlation is used to communicate the uncertainty in kriged predictions to a range of audiences (ii) that it is used to explore sensitivity to block size when planning mapping and (iii) as a general operational rule a block size is selected to give a block concordance correlation of 0.8 or larger where this can be achieved without extra sampling.