Spatial Interpolation (Spatial variability)
…the geo-registered soil
samples form a pattern of
“spikes” throughout the
field.  Spatial Interpolation
is similar to throwing a
blanket over the spikes that
conforms to the pattern.
…all interpolation algorithms assume that
1) “nearby things are more alike than
distant things” (spatial autocorrelation),
2) appropriate sampling intensity, and 3)
suitable sampling pattern.
…the continuous surfaces produced “map
the spatial variation in the data samples.
(Berry)