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.

`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.

## 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")
```