aggregateColor: Summarize Soil Colors

In aqp: Algorithms for Quantitative Pedology

Summarize Soil Colors

Description

Summarize soil color data, weighted by occurrence and horizon thickness.

Usage

aggregateColor(
  x,
  groups = "genhz",
  col = "soil_color",
  colorSpace = "CIE2000",
  k = NULL,
  profile_wt = NULL,
  mixingMethod = c("estimate", "exact")
)

Arguments

x	a SoilProfileCollection object
groups	the name of a horizon or site attribute used to group horizons, see examples
col	the name of a horizon-level attribute with soil color specified in hexadecimal (i.e. "#rrggbb")
colorSpace	the name of color space or color distance metric to use for conversion of aggregate colors to Munsell; either CIE2000 (color distance metric), LAB, or sRGB. Default = 'CIE2000'
k	single integer specifying the number of colors discretized via PAM (cluster package), see details
profile_wt	the name of a site-level attribute used to modify weighting, e.g. area
mixingMethod	method used to estimate "aggregate" soil colors, see mixMunsell

Details

Weights are computed by: w_i = sqrt(sum(thickness_i)) * n_i where w_i is the weight associated with color i, thickness_i is the total thickness of all horizons associated with the color i, and n_i is the number of horizons associated with color i. Weights are computed within groups specified by groups.

Value

A list with the following components:

scaled.data	a list of colors and associated weights, one item for each generalized horizon label with at least one color specified in the source data
aggregate.data	a data.frame of weighted-mean colors, one row for each generalized horizon label with at least one color specified in the source data

Author(s)

D.E. Beaudette

See Also

generalize.hz

Examples

# load some example data
data(sp1, package='aqp')

# upgrade to SoilProfileCollection and convert Munsell colors
sp1$soil_color <- with(sp1, munsell2rgb(hue, value, chroma))
depths(sp1) <- id ~ top + bottom
site(sp1) <- ~ group

# generalize horizon names
n <- c('O', 'A', 'B', 'C')
p <- c('O', 'A', 'B', 'C')
sp1$genhz <- generalize.hz(sp1$name, n, p)

# aggregate colors over horizon-level attribute: 'genhz'
a <- aggregateColor(sp1, groups = 'genhz', col = 'soil_color')

# aggregate colors over site-level attribute: 'group'
a <- aggregateColor(sp1, groups = 'group', col = 'soil_color')

# aggregate colors over site-level attribute: 'group'
# discretize colors to 4 per group
a <- aggregateColor(sp1, groups = 'group', col = 'soil_color', k = 4)

# aggregate colors over depth-slices
s <- slice(sp1, c(5, 10, 15, 25, 50, 100, 150) ~ soil_color)
s$slice <- paste0(s$top, ' cm')
s$slice <- factor(s$slice, levels=guessGenHzLevels(s, 'slice')$levels)
a <- aggregateColor(s, groups = 'slice', col = 'soil_color')

## Not run: 
  # optionally plot with helper function
  if(require(sharpshootR))
    aggregateColorPlot(a)

## End(Not run)

# a more interesting example
## Not run: 
  data(loafercreek, package = 'soilDB')
  
  # generalize horizon names using REGEX rules
  n <- c('Oi', 'A', 'BA','Bt1','Bt2','Bt3','Cr','R')
  p <- c('O', '^A$|Ad|Ap|AB','BA$|Bw', 
         'Bt1$|^B$','^Bt$|^Bt2$','^Bt3|^Bt4|CBt$|BCt$|2Bt|2CB$|^C$','Cr','R')
  loafercreek$genhz <- generalize.hz(loafercreek$hzname, n, p)
  
  # remove non-matching generalized horizon names
  loafercreek$genhz[loafercreek$genhz == 'not-used'] <- NA
  loafercreek$genhz <- factor(loafercreek$genhz)
  
  a <- aggregateColor(loafercreek, 'genhz')
  
  # plot results with helper function
  par(mar=c(1,4,4,1))
  aggregateColorPlot(a, print.n.hz = TRUE)
  
  # inspect aggregate data
  a$aggregate.data

## End(Not run)

aqp documentation built on April 12, 2022, 1:05 a.m.