Estimate dry soil colors from moist soil colors and vice versa.

Source: R/estimateSoilColor.R

Soil color is typically described at dry and moist conditions. This function attempts to estimate soil color at dry or moist condition when one is missing. Estimation proceeds as:

  • convert Munsell notation to CIELAB color coordinates via munsell2rgb()

  • apply scaling, rotation, and translation parameters in CIELAB color space

  • locate closest Munsell chip to CIELAB coordinates via col2munsell()

Estimation of dry from moist soil color state is not guaranteed to be symmetric with estimation of moist from dry.

estimateSoilColor(hue, value, chroma, sourceMoistureState = c("dry", "moist"))

Arguments

hue

vector of Munsell hue ('10YR', '2.5Y', etc.)

value

vector of Munsell value (2,2.5 2.5, 3, 5, 6, etc.)

chroma

vector of Munsell chroma (2, 3, 4, etc.)

sourceMoistureState

character, source colors are either 'dry' or 'moist'

Value

data.frame of estimated colors in Munsell notation. The sigma column contains CIE2000 color contrast metric values describing the perceptual distance between estimated color in CIELAB coordinates and closest Munsell chip.

Details

Scaling, rotation, and translation parameters for shifting between dry <--> moist CIELAB coordinates was determined using vegan::procrustes(), from those official series descriptions (OSD) where moist and dry soil colors were available.

Estimates for colors having a (dry or moist) Munsell value of 10 are not likely correct.

This is still a work in progress.

Author

D.E. Beaudette

Examples


# keep examples from using more than 2 cores
data.table::setDTthreads(Sys.getenv("OMP_THREAD_LIMIT", unset = 2))

estimateSoilColor(hue = '10YR', value = 3, chroma = 3, sourceMoistureState = 'moist')
#>    hue value chroma    sigma
#> 1 10YR     5      3 3.875902

# note that estimation is not symmetric
estimateSoilColor(hue = '10YR', value = 5, chroma = 3, sourceMoistureState = 'dry')
#>    hue value chroma    sigma
#> 1 10YR     4      3 4.162624