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This function is used to compare the distribution of discharges in the sample data set and the discharges in the full daily data set. Note that discharge is plotted on a logarithmic axis. The boxplot is created using the log values but the scale is presented in the original units. An ideal situation would show the two boxes roughly similar to each other or the sample boxplot having median, upper quartile, and higher values being slightly greater than in the boxplot of all days.

Box widths are proportional to the square root of the number of observations (left box based on number of sampled days, right box based on total number of days in the record).

Data come from named list, which contains a Sample dataframe with the sample data, a Daily dataframe with the daily flow data, and an INFO dataframe with metadata.

Although there are a lot of optional arguments to this function, most are set to a logical default.


boxQTwice(eList, printTitle = TRUE, qUnit = 2, cex = 0.8,
  cex.main = 1.1, logScale = TRUE, cex.axis = 1.1, tcl = 0.5,
  las = 1, tinyPlot = FALSE, usgsStyle = FALSE, customPar = FALSE, ...)



named list with at least the Daily, Sample, and INFO dataframes


logical variable if TRUE title is printed, if FALSE not printed (this is best for a multi-plot figure)


object of qUnit class printqUnitCheatSheet, or numeric represented the short code, or character representing the descriptive name.


numerical value giving the amount by which plotting symbols should be magnified


magnification to be used for main titles relative to the current setting of cex


logical if TRUE y plotted in log axis. Defaults to TRUE.


magnification to be used for axis annotation relative to the current setting of cex


number defaults to 0.5, specifies length of tick marks as fraction of height of a line of text


numeric in 0,1,2,3; the style of axis labels, see ?par


logical variable, if TRUE plot is designed to be plotted small as part of a multi-plot figure, default is FALSE.


logical option to use USGS style guidelines. Setting this option to TRUE does NOT guarantee USGS compliance. It will only change automatically generated labels.


logical defaults to FALSE. If TRUE, par() should be set by user before calling this function


arbitrary graphical parameters that will be passed to genericEGRETDotPlot function (see ?par for options)

See also


eList <- Choptank_eList
# Water year:

boxQTwice(eList, qUnit=1)
boxQTwice(eList, qUnit='cfs')

# Graphs consisting of Jun-Aug
eList <- setPA(eList, paStart=6,paLong=3)