PRODUCING A VARIOGRAM

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There are 400 data items and these provide 79800 pairs of observations (400 x 399 / 2). To estimate average differences in Z as a function of the distance separating points, we group pairs of points by their separation distances (h).

We calculate the mean squared difference between pairs of measurements within a group.

Mean separation Number of pairs Mean squared difference
h n v
e.g.
0 - 12 0 *
13 - 24 1102 448.8
25 - 36 2376 600.5
.
.

Note : It is advisable to have at least 150 observations to provide reliable variogram estimates.

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Variogram analysis 12.11.97 Page : 3 of 12