aqp: soilColorSignature – R documentation

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aqp

soilColorSignature

Soil Profile Color Signatures

Description

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

Usage

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

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

Details

See the related tutorial.

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 ...

Author(s)

D.E. Beaudette

References

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

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)

aqp

Algorithms for Quantitative Pedology

v1.29

GPL (>= 3)

Authors

Dylan Beaudette [aut, cre], Pierre Roudier [aut, ctb], Andrew Brown [aut, ctb]

Initial release

2021-04-05