get_head_outliers {mlms} | R Documentation |
Detect Hydraulic Head Outliers
Description
Detect outliers in the fluid pressure data by comparing parameter values
against statistical metrics derived from the heads
dataset.
This function will employ both the standard score (z-score) and Interquartile Range (IQR)
methods for outlier identification.
Usage
get_head_outliers(
data = mlms::heads,
vars = NULL,
method = c("z-score", "IQR"),
threshold = 3,
multiplier = 1.5,
min_n = 10L,
quiet = TRUE
)
Arguments
data |
'data.frame' table.
Depth-discrete measurements of fluid pressure and temperature, hydraulic head values,
and land-surface atmospheric pressure measurements.
Defaults to the |
vars |
'character' vector. One or more variable names for which to compute summary statistics. Choices include: "total_head_va" is the hydraulic head in feet above the North American Vertical Datum of 1988, "temp_va" is the fluid temperature in degree Celsius, "baro_va" is the atmospheric pressure in pounds per square inch absolute (psi), and "press_va" is the absolute fluid pressure in psi. By default, all variables are included. |
method |
'character' string. Outlier detection method. Specify "z-score" (default) for the standard score method, best suited for normally distributed data, or "IQR" to use the IQR method, which is ideal for skewed distributions. |
threshold |
'numeric' number. Z-score value used to determine whether a parameter value is considered an outlier or significantly different from the historic mean value. |
multiplier |
'numeric' number. Multiplier used to determine the threshold for outliers in the IQR method. |
min_n |
'integer' number. Minimum sample size needed to detect outliers. |
quiet |
'logical' flag. Whether to suppress printing of outlier information. |
Value
A data frame with the following variables:
var_ds
Variable description.
var_nm
Variable name as specified in the
vars
argument.site_nm
Local site name for a MLMS well.
port_nu
Identifier for the valved measurement port, included only if the
by_port
argument is set to true (not the default).press_dt
Time at which measurements were measured outside the multiport casing.
var_va
Parameter value.
z_score
Z-score, a statistical measure that indicates how many standard deviations a parameter value is from the mean.
qu_1st
First quartile (25th percentile) of historical parameter values.
qu_3rd
Third quartile (75th percentile) of historical parameter values.
n
Sample size.
Author(s)
J.C. Fisher, U.S. Geological Survey, Idaho Water Science Center
See Also
get_head_stats
function is used to calculate the fluid pressure statistics.
Examples
d <- get_head_outliers()
str(d)
d <- get_head_outliers(method = "IQR")
str(d)