drc (version 1.2-0)

plot.drc: Plotting fitted curves for a drc object

Description

'plot' displays fitted curves and observations in the same plot window, distinguishing between curves by different plot symbols and line types.

Usage

## S3 method for class 'drc':
plot(x, ..., level = NULL, broken = FALSE, col = FALSE, 
  conLevel, conName, grid = 100, legend, legendText, legendPos,
  type = "average", obs, lty, log = "x", pch, xlab, ylab, xlim, ylim,
  bcontrol = NULL, xt = NULL, xtlab = NULL, yt = NULL, ytlab = NULL,
  add = FALSE)

Arguments

x

an object of class 'drc'. For instance, 'lwd=2' or 'lwd=3' increase the width of plot symbols.

...

additional arguments.

level

vector of character strings. To plot only the curves specified by their names.

broken

logical. If TRUE the x axis is broken provided this axis is logarithmic (requires the CRAN package 'plotrix').

col

either logical or a vector of colours. If TRUE default colours are used. If FALSE (default) no colours are used.

conLevel

numeric. Dose level below which the dose is zero (the amount of stretching on the x-axis above zero). Default is 1e-2.

conName

character string. Name on x axis for dose zero. Default is '"0"'.

grid

numeric. Number of points in the grid used for plotting the fitted curves.

legend

logical. If TRUE a legend is displayed.

legendText

a character string or vector of character strings specifying the legend text.

legendPos

numeric vector of length 2 giving the position of the legend.

type

a character string specifying how the originals observations should be plotted. There are 4 options: "average" (default), "none" (only the fitted curve(s)), "obs" (only the data points), "all" or "points" (all data points).

obs

Outdated argument. Use type.

lty

a numeric vector specifying the line types.

log

a character string which contains '"x"' if the x axis is to be logarithmic, '"y"' if the y axis is to be logarithmic and '"xy"' or '"yx"' if both axes are to be logarithmic. The default is "x". The empty string "" yields the original axes.

pch

a vector of plotting characters or symbols (see points).

xlab

an optional label for the x axis.

ylab

an optional label for the y axis.

xlim

a numeric vector of length two, containing the lower and upper limit for the x axis.

ylim

a numeric vector of length two, containing the lower and upper limit for the y axis.

bcontrol

a list. Controlling the appearance of the break (if 'broken' is TRUE).

xt

a numeric vector containing the positions of the tick marks on the x axis.

xtlab

a vector containing the tick marks on the x axis.

yt

a numeric vector, containing the positions of the tick marks on the y axis.

ytlab

a vector containing the tick marks on the y axis.

add

logical. If TRUE then add to already existing plot.

Value

• An invisible data frame with the values used for plotting the fitted curves. The first column contains the dose values, and the following columns (one for each curve) contain the fitted response values.

Details

Suitable labels are automatically provided. The use of xlim allows changing the x-axis, extrapolating the fitted dose-response curves. See colors for the available colours.

See Also

plotraw plots the observations only.

Examples

## Fitting models to be plotted below
model1 <- multdrc(rootl~conc, data = ryegrass)
model2 <- multdrc(rootl~conc, data = ryegrass, fct=l3())  # lower limit fixed at 0

## Plotting observations and fitted curve for 'model1'
plot(model1) 

## Adding fitted curve for 'model2'
plot(model2, add = TRUE, type = "none", 
col = 2, lty = 2)

## Fitting model to be plotted below
model3 <- multdrc(SLOPE~DOSE, CURVE, data=PestSci)

## Plot with no colours
plot(model3, main="Different line types (default)")

## Plot with default colours
plot(model3, col=TRUE, main="Default colours")

## Plot with specified colours
plot(model3, col=c(2,6,3,23,56), main="User-specified colours")

## Plot of curves 1 and 2 only
plot(model3, level=c(1,2), main="User-specified curves")

## Fitting another model to be plotted below
model4 <- multdrc(weight~conc, data=hormesis)

## Using the argument 'conLevel'. Compare the plots!
par(mfrow=c(2, 2))
plot(model4, main="conLevel=1e-2 (default)")  # using the default
plot(model4, conLevel=1e-4, main="conLevel=1e-4")
plot(model4, conLevel=1e-6, main="conLevel=1e-6")
plot(model4, conLevel=1e-8, main="conLevel=1e-8")
par(mfrow=c(1,1))

## Using the argument 'broken'
plot(model1, conLevel = 0.1, broken = TRUE)
plot(model1, conLevel = 0.1, broken = TRUE, 
bcontrol=list(style="zigzag"))

## Removing models from work space
rm(model1, model2, model3, model4)