soil.texture {plotrix}R Documentation

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.

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.

Value

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

Note

This is now a special case of triax.plot.

Author(s)

Sander Oom, Jim Lemon, and Michael Toews

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)
 soiltex.return<-soil.texture(soils[1:6,], main="GRID AND LEGEND",
  show.grid=TRUE, pch=4, col.symbols=1:6, show.legend=TRUE)
 par(soiltex.return$oldpar)

[Package plotrix version 2.5-5 Index]