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("V", "A", "C", "G", "D"),
  offset = c(0.5, 2, 5, 15, 20)/2
)

Arguments

x

vector of boundary distinctness codes to be converted

codes

code values, adjust as needed

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.

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

References

Field Book for Describing and Sampling Soils, version 3.0

See also

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

# 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')


# clean-up
par(op)