sfplot {spreval}

Create step function plot (of catch can depths).

Description

Uses an 'stats::ecdf' object to plot a step function plot with cumulative frequency on x axis and input array (catch can depths) on y axis with y-axis reversed (min(y)= 0 at top of y-axis). Top of plot represents soil surface.

Usage

sfplot(x,target=NA,xlab=NULL,ylab=NULL,...)

Arguments

x

numeric array

target

target, a constant, e.g., target depth of irrigation.

xlab

label for x axis, standard default provided.

ylab

label for y axis, e.g., depth applied. Default is name of object x if not supplied.

...

further graphical parameters to pass to internal calls to plot.default

Details

Plot includes step function lines unlike rotecdf. A minimum y of 0 is forced such that the plot can be interpreted as 0 being ground surface. If "target" is supplied, a horizontal line at the value of target is drawn. Points and area below the target line indicate water applied in excess of the target amount.

Value

Step function plot as empirical cumulative distribution function with x on y-axis and f(x), i.e., cum. prob., on x-axis.

Note

Wrapper functions for internally called plot and sub-plot functions within 'rotecfd' prevent warnings and errors for graphical parameters passed via '...' that are not recognized by subplolot functions, i.e., abline, text. Therefore not all graphical parameters passed via '...' will be realized in the generated plot.

Author(s)

Garry Grabow [e-mail]

See Also

rotecdf,stepfun,ecdf

Examples

target<-3
# generate data with mean of target amount and high variability (non-uniformity)
x<-rnorm(25,3,1.75)
sfplot(x,target,ylab="depth applied (caught)")
# generate data with mean of target amount and low varibility (uniformity)
xx<-rnorm(25,3,0.5)
sfplot(xx,target)#no y axis label provided - defaults to array object name
#customize graphical parameters
sfplot(xx,target,main="Good uniformity",xlab="cum. probability",lwd=2, col="blue")