plotrix (version 2.5-2)

soil.texture.uk: Soil texture triangle plot using UK conventions

Description

Display a UK style soil texture triangle with optional grid, labels and soil texture points.

Usage

soil.texture.uk(soiltexture = NULL, main = "",at = seq(0.1, 0.9, by = 0.1),
  axis.labels = c("percent sand", "percent silt", "percent clay"),
  tick.labels = list(l = seq(10, 90, by = 10), r = seq(10, 90, by = 10),
  b = seq(10, 90, by = 10)), show.names = TRUE,
  show.lines = TRUE, col.names = "gray", bg.names = par("bg"),
  show.grid = FALSE, col.axis = "black", col.lines = "gray",
  col.grid = "gray", lty.grid = 3, show.legend = FALSE, label.points = FALSE,
  point.labels = NULL, col.symbols = "black", pch = par("pch"),
  h1 = NA, h3 = NA, t1 = NA, t3 = NA, lwduk = 2, xpos = NA, ypos = NA,
  snames = NA, cexuk = 1.1, ...)

Arguments

soiltexture

Matrix of soil textures where each row is a soil sample and three columns containing the percentages of the components sand, silt and clay in the range 0 to 100.

main

The title of the soil texture plot. Defaults to nothing.

at

Positions on the three axes where ticks will be drawn.

axis.labels

Labels for the axes.

tick.labels

The tick labels for the three axes.

show.names

Logical - whether to show the names of different soil types within the soil triangle.

show.lines

Logical - whether to show the boundaries of the different soil types within the soil triangle.

col.names

Color of the soil names. Defaults to gray.

bg.names

Color to use when drawing a blank patch for the names of soil types.

show.grid

Logical - whether to show grid lines at each 10 level of each soil component.

col.axis

Color of the triangular axes, ticks and labels.

col.lines

Color of the boundary lines. Defaults to gray.

col.grid

Color of the grid lines. Defaults to gray.

lty.grid

Type of line for the grid. Defaults to dashed.

show.legend

Logical - whether to display a legend.

label.points

Logical - whether to call thigmophobe.labels to label the points.

point.labels

Optional labels for the points or legend.

col.symbols

Color of the symbols representing each value.

pch

Symbols to use in plotting values.

h1,h3,t1,t3

Points used in drawing boundaries for soil types.

lwduk

Line width for the boundaries

xpos,ypos

Positions for the soil type labels.

snames

Soil type labels.

cexuk

Character expansion for the soil type labels.

...

Additional arguments passed to triax.points and then points.

Value

• If soiltexture was included, a list of the x,y positions of the soil types plotted. If not, nil.

Details

soil.texture.uk displays a triangular plot area on which soil textures defined as proportions of sand, silt and clay can be plotted. It is similar to the soil.texture function but uses the UK display conventions.

See Also

triax.plot

Examples

soils.sw.percent<-data.frame(
  Sand=c(67,67,66,67,36,25,24,59,27,9,8,8,20,
  45,50,56,34,29,39,41,94,98,97,93,96,99),
  Silt=c(17,16,9,8,39,48,54,27,46,70,68,68,66,
  34,30,24,48,53,46,48,2,2,2,4,1,1),
  Clay=c(16,17,25,25,25,27,22,14,27,21,24,24,
  14,21,20,20,18,18,15,11,4,0,1,3,3,0))
 soils.sw.cols <- c(1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3,
  3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6)
 soils.sw.names <- c("Ardington","Astrop","Atrim",
  "Banbury","Beacon","Beckfoot")
 soil.texture.uk(soils.sw.percent,
  main = "Ternary Diagram for Some Soils from South West England",
  col.lines = "black", col.names = "black", show.grid = TRUE,
  col.grid = "blue", lty.grid = 2,  pch = 16, cex = 1.0,
  col.symbols = soils.sw.cols, h1 = NA, h3 = NA, t1 = NA,
  t3 = NA , lwduk = 2, xpos = NA, ypos = NA,
  snames = NA, cexuk = 1.1)
 legend("topleft", legend = soils.sw.names, col = 1:max(soils.sw.cols),
  pch = 16, cex = 1.1, title = "Location", bty = "n")