aqp (version 1.18)

colorQuantiles: Soil Color Range via Quantiles

Description

Estimate central tendency and spread of soil color using marginal quantiles and L1 median of CIELAB coordinates.

Usage

colorQuantiles(soilColors, p = c(0.05, 0.5, 0.95))
plotColorQuantiles(res, pt.cex=7, title='', mar=c(2,1.5,1,1))

Arguments

soilColors

vector of R colors (sRGB colorspace)

p

marginal quantiles of interest

res

list returned by colorQuantiles

pt.cex

scaling factor for color chips

title

optional title printed above color quantile figure

mar

customized margins, see details

Value

A List containing the following elements:

marginal

data.frame containing marginal quantiles in CIELAB (D65), closest colors and Munsell chips

L1

L1 median CIELAB (D65) values, closest color and Munsell chip

Details

Colors are converted from sRGB to CIELAB (D65 illuminant), marginal quantiles of L,A,B coordinates are estimated, and L1 median L,A,B is estimates. The closest Munsell chips (via Musell/CIELAB lookup table provided by munsell) and R colors are determined by locating chips closest to the marginal quantiles and L1 median.

The results can be conveniently inspected using plotColorQuantiles.

Examples

# NOT RUN {
# example data, see manual page for details
data(sp5)

# slice top 25 cm
s <- slice(sp5, 1:25 ~ .)

# check some of the data
par(mar=c(0,0,0,0))
plot(sample(s, 25), divide.hz=FALSE, name='', print.id=FALSE, width=0.5)

# colors
previewColors(unique(s$soil_color))

# compute marginal quantiles and L1 median
cq <- colorQuantiles(s$soil_color)

# simple graphical display of results
plotColorQuantiles(cq)
# }