plotrix (version 2.3-1)

soil.texture: Soil texture triangle plot

Description

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

Usage

soil.texture(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"), ...)

Arguments

soiltexture

Matrix of soil textures where each row is a soil sample and three columns contain the proportions of the components sand, silt and clay in the range 0 to 1 or percentages 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.

...

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 displays a triangular plot area on which soil textures defined as proportions of sand, silt and clay can be plotted. Optional grid, vertex labels, soil type divisions and names may also be displayed. If a matrix of soil textures is present, these will be plotted.

References

U.S. Department of Agriculture, Natural Resources Conservation Service, 2007. National Soil Survey Handbook, title 430-VI.// http://soils.usda.gov/technical/handbook/

U.S. Department of Agriculture, Natural Resources Conservation Service, 2007. Soil Texture Calculator// http://soils.usda.gov/technical/aids/investigations/texture/

See Also

get.soil.texture, triax.plot

Examples

data(soils)
 soil.texture(main="NO DATA")
 soil.texture(soils, main="DEFAULT", pch=2)
 soil.texture(soils, main="LINES AND NAMES", show.lines=TRUE,
  show.names=TRUE, pch=3)
 soil.texture(soils[1:6,], main="GRID AND LEGEND",
  show.grid=TRUE, pch=4, col.symbols=1:6, show.legend=TRUE)