Create a (redundant) horizon-level attribute from a site-level attribute. Specify a SoilProfileCollection and a site-level attribute from that SPC (by name) to receive a vector of length equal to the number of horizons containing the site-level values. This vector is directly usable with the SoilProfileCollection horizon setter.
denormalize is the inverse operation for the formula interface that "normalizes" a horizon level variable to site level:
site(object) <- ~ horizonvar
Site-level attribute name (character string) to denormalize to horizon.
"Denormalization" is the process of trying to improve the read performance of a database, at the expense of losing some write performance, by adding redundant copies of data or by grouping data. Sometimes it is beneficial to have site-level attributes denormalized for grouping of horizon-level data in analyses.
denormalize achieves this result for SoilProfileCollections.
A vector of values of equal length to the number of rows in the horizon table of the input SPC.
Andrew G. Brown, Dylan Beaudette
data(sp1) # create a SoilProfileCollection from horizon data depths(sp1) <- id ~ top + bottom # create random site-level attribute `sitevar` with a binary (0/1) outcome sp1$sitevar <- round(runif(length(sp1))) # use denormalize() to create a mirror of sitevar in the horizon table # name the attribute something different (e.g. `hz.sitevar`) to # prevent collision with the site attribute # the attributes can have the same name but you will then need # site() or horizons() to access explicitly sp1$hz.sitevar <- denormalize(sp1, 'sitevar') # compare number of profiles to number of sitevar assignments length(sp1) table(sp1$sitevar) # compare number of horizons to number of horizon-level copies of sitevar `hz.'sitevar` nrow(sp1) table(sp1$hz.sitevar)
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