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Last data update: 2014.03.03

R: Barchart of recession length

seglenplot

R Documentation

Barchart of recession length

Description

Plots a barchart to find a good value for 'seglength' when using recession.

Usage

seglenplot(lfobj,
           threslevel = 70,
           thresbreaks = c("fixed","monthly","seasonal"),
           thresbreakdays = NULL,
           rainpeaklevel = 0.95,
           na.rm = TRUE)

Arguments

`lfobj`	An object of class "lfobj"
`threslevel`	The threshold level (70 means Q70)
`thresbreaks`	"fixed" uses a fixed threshold level, "monthly" calculates the threshold for every month separatly, "seasonal" calculates thresholds for every season defined using "thresbreakdays".
`thresbreakdays`	Needed if "thresbreaks = 'seasonal'" to define the periodes for which separate thresholds should be calculated, see details
`rainpeaklevel`	A level between 0 and 1 or a logical vector, see details.
`na.rm`	Should NAs in the series be ignored?

Details

For recession analysis it is neccessary to define flood discharge peaks (rainpeaks) in the hydrograph. Rainpeaklevel defines a day to be a descharge peak, if rainpeaklevel * flow > flow[day before] and rainpeaklevel * flow > flow[day after].

If thresbreakdays or seasonbreakdays is a single day, e.g. "01/06", the start of the hydrological year is taken as the second breakday. If more than two seasons are to be specified, a vector of all breakdays is needed.

Value

A barchart

Warning

Other then in the manual, we implemented a barchart instead of a histogram. To save space, empty bars are not plotted!

Author(s)

Daniel Koffler and Gregor Laaha

References

Gustard, A. & Demuth, S. (2009) (Eds) Manual on Low-flow Estimation and Prediction. Operational Hydrology Report No. 50, WMO-No. 1029, 136p.

Examples

## Not run: 
data(ngaruroro)
seglenplot(ngaruroro)
## End(Not run)