Horizons Above or Below
hzAbove(x, ..., offset = 1, SPC = TRUE, simplify = SPC)
hzBelow(x, ..., offset = 1, SPC = TRUE, simplify = SPC)
hzOffset(x, hzid, offset, SPC = FALSE, simplify = TRUE)A SoilProfileCollection
Comma-separated set of R expressions that evaluate as TRUE or FALSE in context of horizon data frame. Length for individual expressions matches number of horizons, in x.
Integer offset in terms of SoilProfileCollection [,j] (horizon/slice) index
Return a SoilProfileCollection? Default TRUE for horizon_* methods.
If TRUE return a vector (all elements combined), or a list (1 element per profile). If SPC is TRUE then simplify is TRUE.
A vector of target horizon IDs. These are calculated from ... for horizon_*() methods
A SoilProfileCollection (when SPC = TRUE) or a vector of horizon row indices (when SPC = FALSE and simplify = TRUE) or a list (when SPC = FALSE and simplify = FALSE))
To minimize likelihood of issues with non-standard evaluation context, especially when using hzAbove()/hzBelow() inside another function, all expressions used in ... should be in terms of variables that are in the horizon data frame.
data(sp4)
depths(sp4) <- id ~ top + bottom
# get the horizon above the last horizon (j-index of bottom horizon minus 1)
hzAbove(sp4, hzID(sp4) %in% getLastHorizonID(sp4))
#> Error: unable to find an inherited method for function ‘hzID’ for signature ‘object = "data.frame"’
# get horizons below the last horizon (none; j-index of bottom horizon plus 1)
hzBelow(sp4, hzID(sp4) %in% getLastHorizonID(sp4))
#> Error: unable to find an inherited method for function ‘hzID’ for signature ‘object = "data.frame"’