Soil Texture Low-RV-High as Defined by Quantiles

This function accepts soil texture components (sand, silt, and clay percentages) and plots a soil texture triangle with a "representative value" (point) and low-high region (polygon) defined by quantiles (estimated with Hmisc::hdquantile). Marginal quantiles of sand, silt, and clay are used to define the boundary of a low-high region. The default settings place the RV symbol at the texture defined by marginal medians of sand, silt, and clay. The default low-high region is defined by the 5th and 95th marginal percentiles of sand, silt, and clay.

textureTriangleSummary(
  ssc,
  p = c(0.05, 0.5, 0.95),
  delta = 1,
  rv.col = "red",
  range.border = "black",
  range.col = "RoyalBlue",
  range.alpha = 80,
  range.lty = 1,
  range.lwd = 2,
  main = "Soil Textures",
  legend.cex = 0.75,
  legend = TRUE,
  ...
)

Arguments

ssc

data.frame with columns: 'SAND', 'SILT', 'CLAY', values are percentages that should add to 100. No NA allowed.

p

vector of percentiles (length = 3) defining 'low', 'representative value', and 'high'

delta

grid size used to form low-high region

rv.col

color used for representative value (RV) symbol

range.border

color used for polygon border enclosing the low-high region

range.col

color used for polygon enclosing the low-high region

range.alpha

transparency of the low-high range polygon (0-255)

range.lty

line style for polygon enclosing the low-high region

range.lwd

line weight polygon enclosing the low-high region

main

plot title

legend.cex

scaling factor for legend

legend

logical, enable/disable automatic legend

...

further arguments passed to soiltexture::TT.points

Value

an invisible matrix with marginal percentiles of sand, silt, and clay

See also

bootstrapSoilTexture

Author

D.E. Beaudette, J. Nemecek, K. Godsey

Examples

# \donttest{

if(
requireNamespace("Hmisc") &
  requireNamespace("compositions") &
  requireNamespace("soiltexture")
) {
  
  # sample data
  data('sp4')
  
  # subset rows / columns
  ssc <- sp4[grep('^Bt', sp4$name), c('sand', 'silt', 'clay')]
  names(ssc) <- toupper(names(ssc))
  
  # make figure, marginal percentiles are silently returned
  stats <- textureTriangleSummary(
    ssc, pch = 1, cex = 0.5, 
    range.alpha = 50, 
    range.lwd = 1,
    col = grey(0.5), 
    legend = FALSE
  )
  
  # check
  stats
  
  # simulate some data and try again
  s <- bootstrapSoilTexture(ssc, n = 100)$samples
  
  # make the figure, ignore results
  textureTriangleSummary(
    s, pch = 1, cex = 0.5, 
    range.alpha = 50, 
    range.lwd = 1,
    col = grey(0.5), 
    legend = FALSE
  )
}



# }