Apply rate-of-change QC flag

Usage

utilASRflagroc(flag, vals, datetimes, dqo)

Arguments

flag: character vector of current flag values ("pass", "suspect", or "fail").
vals: numeric vector of observed values, the same length as flag.
datetimes: POSIXct vector of observation timestamps, the same length as flag.
dqo: two-row data frame from data quality objectives for the parameter being checked, containing one row where Flag == "Fail" and one where Flag == "Suspect". The "Suspect" row's numeric columns RoCN (SD multiplier) and RoCHours (trailing window width in hours) control the check. If either column is NA in the "Suspect" row the check is skipped. Rate-of-change thresholds are not applied to "Fail" flags.

Value

Updated character flag vector.

Details

For each observation the standard deviation of all raw values within a trailing RoCHours-hour window ending at (and including) that observation is multiplied by RoCN to produce a threshold. The observation is flagged "suspect" if the absolute lag-1 difference exceeds that threshold. At least 2 values must fall within the window to compute the standard deviation; otherwise the observation is skipped. This check only produces "suspect" flags; it does not produce "fail" flags.

Examples

flag <- rep("pass", 6)
vals <- c(10, 10.2, 10.1, 10.3, 15.0, 10.2)
datetimes <- as.POSIXct("2024-01-01") + seq(0, 5) * 900  # 15-min intervals
dqo <- data.frame(Flag = c("Fail", "Suspect"), RoCN = c(NA, 3), RoCHours = c(NA, 2))
utilASRflagroc(flag, vals, datetimes, dqo)
#> [1] "pass" "pass" "pass" "pass" "pass" "pass"