group4: Calculate the group 4 IHA parameters.

In IHA: This package implements The Nature Conservancy's Indicators of Hydrologic Alteration software in R.

Description

The group 4 IHA parameters measure the frequency and duration of high and low pulses.

Usage

  group4(x, year = c("water", "calendar"),
    thresholds = NULL)

Arguments

thresholds	vector of length 2; the cut off for a low pulse and a high pulse, respectively
x	A zoo object containing the flow series
year	the type of year factor to be used, yr = 'water' or yr = 'calendar' for water years and calendar years respectively

Details

By default, the pulse thresholds are the 25th and 75th percentiles of the distribution of flows. TNC's IHA software uses the quantile as defined http://www.roguewave.com/portals/0/products/imsl-numerical-libraries/c-library/docs/8.0/html/cstat/stat.htm which corresponds to R's type = 6 option in quantile. The default thresholds here are calculated using R's default type = 7 option.

Value

a matrix of group 3 parameters

Author(s)

[e-mail]

References

http://www.conservationgateway.org/Files/Pages/indicators-hydrologic-altaspx47.aspx

Examples

data(bullrun)
group4(bullrun)

IHA documentation built on May 2, 2019, 5:15 p.m.