Soil Profile Color Signatures

Generate a color signature for each soil profile in a collection.

soilColorSignature(
  spc,
  r = "r",
  g = "g",
  b = "b",
  method = c("colorBucket", "depthSlices", "pam"),
  pam.k = 3,
  RescaleLightnessBy = 1,
  useProportions = TRUE,
  pigmentNames = c(".white.pigment", ".red.pigment", ".green.pigment", ".yellow.pigment",
    ".blue.pigment"),
  apply.fun = lapply
)

Arguments

spc

a SoilProfileCollection object

r

horizon level attribute containing soil color (sRGB) red values

g

horizon level attribute containing soil color (sRGB) green values

b

horizon level attribute containing soil color (sRGB) blue values

method

algorithm used to compute color signature, colorBucket, depthSlices, or pam

pam.k

number of classes to request from cluster::pam()

RescaleLightnessBy

rescaling factor for CIE LAB L-coordinate

useProportions

use proportions or quantities, see details

pigmentNames

names for resulting pigment proportions or quantities

apply.fun

function passed to aqp::profileApply(APPLY.FUN) argument, can be used to add progress bars via pbapply::pblapply, or parallel processing with furrr::future_map

Value

For the colorBucket method, a data.frame object containing:

• id column: set according to idname(spc)

• .white.pigment: proportion or quantity of CIE LAB L-values

• .red.pigment: proportion or quantity of CIE LAB positive A-values

• .green.pigment: proportion or quantity of CIE LAB negative A-values

• .yellow.pigment: proportion or quantity of CIE LAB positive B-values

• .blue.pigment: proportion or quantity of CIE LAB negative B-values

Column names can be adjusted with the pigmentNames argument.

For the depthSlices method ...

For the pam method ...

Details

See the related tutorial.

References

https://en.wikipedia.org/wiki/Lab_color_space

See also

munsell2rgb

Author

D.E. Beaudette

Examples

# trivial example, not very interesting
data(sp1)
depths(sp1) <- id ~ top + bottom

# convert Munsell -> sRGB triplets
rgb.data <- munsell2rgb(sp1$hue, sp1$value, sp1$chroma, return_triplets = TRUE)
sp1$r <- rgb.data$r
sp1$g <- rgb.data$g
sp1$b <- rgb.data$b

# extract color signature
pig <- soilColorSignature(sp1)