guessGenHzLevels {aqp} | R Documentation |
This function makes an (educated) guess at an appropriate set of levels for generalized horizon labels using the median of horizon depth mid-points.
guessGenHzLevels(x, hz = "genhz")
x |
a |
hz |
name of horizon-level attribute containing generalized horizon labels, see details |
This function is useful when groups of horizons have been generalized via some method other than generalize.hz
. For example, it may be useful to generalize horizons using labels derived from slice depths. The default sorting of these labels will not follow a logicial depth-wise sorting when converted to a factor. guessGenHzLevels
does a good job of "guessing" the proper ordering of these labels based on median horizon depth mid-point.
a list:
levels |
a vector of levels sorted by median horizon depth mid-point |
median.depths |
a vector of median horizon mid-points |
D.E. Beaudette
# load some example data
data(sp1, package='aqp')
# upgrade to SoilProfileCollection
depths(sp1) <- id ~ top + bottom
# generalize horizon names
n <- c('O', 'A', 'B', 'C')
p <- c('O', 'A', 'B', 'C')
sp1$genhz <- generalize.hz(sp1$name, n, p)
# note: levels are in the order in which originally defined:
levels(sp1$genhz)
## [1] "O" "A" "B" "C" "not-used"
# generalize horizons by depth slice
s <- slice(sp1, c(5, 10, 15, 25, 50, 100, 150) ~ .)
s$slice <- paste0(s$top, ' cm')
# not a factor
levels(s$slice)
## NULL
# the proper ordering of these new labels can be guessed from horizon depths
guessGenHzLevels(s, 'slice')
## $levels
## [1] "5 cm" "10 cm" "15 cm" "25 cm" "50 cm" "100 cm" "150 cm"
##
## $median.depths
## 5 cm 10 cm 15 cm 25 cm 50 cm 100 cm 150 cm
## 5.5 10.5 15.5 25.5 50.5 100.5 150.5
# convert to factor, and set proper order
s$slice <- factor(s$slice, levels=guessGenHzLevels(s, 'slice')$levels)
# that is better
levels(s$slice)
## [1] "5 cm" "10 cm" "15 cm" "25 cm" "50 cm" "100 cm" "150 cm"