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A comparison between mixed support kriging and block cokriging for modelling and combining spatial data with different support

Castrignanò, A., Quarto, R., Venezia, A., Buttafuoco, G.
Precision agriculture 2019 v.20 no.2 pp. 193-213
geostatistics, kriging, models, multivariate analysis, soil electrical conductivity, spatial data, tomatoes, variance
The paper proposes a geostatistical framework to solve the issues of heterogeneous support for spatial estimation. Apparent soil electrical conductivity (ECₐ) was measured in a field cropped with San Marzano tomato using a multiple frequency electromagnetic profiler with six operating frequencies. Mixed support kriging (MSK) was used to estimate ECₐ taking into account the change of support. The method includes punctual kriging with the error being the dispersion variance associated with each frequency. The mixed support kriging approach was compared with traditional block cokriging (BCOK) through cross validation. Block cokriging compared to MSK was more computationally intensive to fit the multivariate model of spatial dependence, and in estimating ECₐ, mixed support kriging outperformed at some frequencies whereas BCOK was more accurate at others. The two approaches were also compared in terms of field-delineation which differed in spatial continuity.