Convert Horizon Boundary Distinctness to Vertical Offset

This function will convert USDA-NCSS horizon boundary distinctness codes into vertical (+/-) offsets in cm, based on the Field Book for Describing and Sampling Soils, version 3.0.

hzDistinctnessCodeToOffset(
  x,
  codes = c("very abrupt", "abrupt", "clear", "gradual", "diffuse"),
  offset = c(0.5, 2, 5, 15, 20)/2
)

Arguments

x

vector of boundary distinctness codes to be converted

codes

character vector of distinctness terms ('clear') or codes ('C'), case insensitive, see details

offset

vertical offset factors (cm), approximating 1/2 of the transitional zone thickness, see details

Value

vector of offsets with same length as x

Details

The default offsets are based on the high-end of ranges presented in "transitional zone thickness criteria" from the Field Book version 3.0 (page 2-6). Offsets are returned as 1/2 of the transitional zone thickness so that horizon boundaries can be adjusted up/down from horizon depths. See plotSPC, specifically the hz.distinctness.offset argument for visualization ideas. Missing data in x (NA) or codes that are not defined in codes are returned as 0 offsets.

Either format (or mixture) are accepted, case insensitive:

• terms: c('very abrupt', 'abrupt', 'clear', 'gradual', 'diffuse')

• coded values: c('v', 'a', 'c', 'g', d')

Additional examples are available in the Visualization of Horizon Boundaries tutorial.

References

Field Book for Describing and Sampling Soils, version 3.0

See also

plotSPC

Author

D.E. Beaudette

Examples

# example data
data(sp1)

# compute 1/2 transitional zone thickness from distinctness codes
sp1$hzdo <- hzDistinctnessCodeToOffset(sp1$bound_distinct)

# convert colors from Munsell to hex-encoded RGB
sp1$soil_color <- with(sp1, munsell2rgb(hue, value, chroma))

# promote to SoilProfileCollection
depths(sp1) <- id ~ top + bottom
hzdesgnname(sp1) <- 'name'

# adjust margins
op <- par(mar=c(0,0,0,1.5))

# sketches, adjust width, adjust text size, include coded hz distinctness offsets
plotSPC(sp1, width=0.3, cex.names=0.75, hz.distinctness.offset = 'hzdo')
#> [P001:6] horizon with top == bottom, cannot fix horizon depth overlap
#>  consider using repairMissingHzDepths()


# clean-up
par(op)