diff options
Diffstat (limited to 'R/PEC_sw_drift.R')
| -rw-r--r-- | R/PEC_sw_drift.R | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/R/PEC_sw_drift.R b/R/PEC_sw_drift.R index c1b24d3..7028101 100644 --- a/R/PEC_sw_drift.R +++ b/R/PEC_sw_drift.R @@ -4,9 +4,16 @@ #' concentration in surface water based on complete, instantaneous mixing #' with input via spray drift. #' +#' It is recommened to specify the arguments `rate`, `water_depth` and +#' `water_width` using [units::units] from the `units` package. +#' #' @inheritParams drift_percentages_rautmann +#' @importFrom units as_units set_units #' @seealso [drift_parameters_focus], [drift_percentages_rautmann] -#' @param rate Application rate in units specified below +#' @param rate Application rate in units specified below, or with units defined via the +#' `units` package. +#' @param rate_units Defaults to g/ha. For backwards compatibility, only used +#' if the specified rate does not have [units::units]]. #' @param drift_percentages Percentage drift values for which to calculate PECsw. #' Overrides 'drift_data' and 'distances' if not NULL. #' @param drift_data Source of drift percentage data. If 'JKI', the [drift_data_JKI] @@ -16,7 +23,6 @@ #' @param crop_group_JKI When using the 'JKI' drift data, one of the German names #' as used in [drift_parameters_focus]. Will only be used if drift_data is 'JKI'. #' @param water_depth Depth of the water body in cm -#' @param rate_units Defaults to g/ha #' @param PEC_units Requested units for the calculated PEC. Only µg/L currently supported #' @param water_width Width of the water body in cm #' @param side_angle The angle of the side of the water relative to the bottom which @@ -49,7 +55,7 @@ #' PEC_sw_drift(100, drift_data = "RF", formula = "FOCUS", side_angle = 45, water_width = 200) PEC_sw_drift <- function(rate, applications = 1, - water_depth = 30, + water_depth = as_units("30 cm"), drift_percentages = NULL, drift_data = c("JKI", "RF"), crop_group_JKI = c("Ackerbau", @@ -59,13 +65,17 @@ PEC_sw_drift <- function(rate, "fruit, late", "fruit, early", "aerial"), distances = c(1, 5, 10, 20), formula = c("Rautmann", "FOCUS"), - water_width = 100, + water_width = as_units("100 cm"), side_angle = 90, rate_units = "g/ha", PEC_units = "\u00B5g/L") { rate_units <- match.arg(rate_units) PEC_units <- match.arg(PEC_units) + # Set default units if not specified + if (!inherits(rate, "units")) rate <- set_units(rate, rate_units, mode = "symbolic") + if (!inherits(water_width, "units")) water_width <- set_units(water_width, "cm") + if (!inherits(water_depth, "units")) water_depth <- set_units(water_depth, "cm") drift_data <- match.arg(drift_data) crop_group_JKI <- match.arg(crop_group_JKI) crop_group_RF <- match.arg(crop_group_RF) @@ -77,10 +87,11 @@ PEC_sw_drift <- function(rate, } formula <- match.arg(formula) if (side_angle < 0 | side_angle > 90) stop("The side anglemust be between 0 and 90 degrees") - mean_water_width <- if (side_angle == 90) water_width + mean_water_width <- if (side_angle == 90) water_width # Mean water width over waterbody depth else water_width - (water_depth / tanpi(side_angle/180)) - water_volume <- 100 * mean_water_width * (water_depth/100) * 1000 # in L (for 1 ha) - PEC_sw_overspray <- rate * 1e6 / water_volume # in µg/L + if (as.numeric(mean_water_width) < 0) stop("Undefined geometry") + relative_mean_water_width <- mean_water_width / water_width # Always <= 1 + PEC_sw_overspray <- set_units(rate / (relative_mean_water_width * water_depth), PEC_units, mode = "symbolic") dist_index <- as.character(distances) if (is.null(drift_percentages)) { @@ -88,7 +99,7 @@ PEC_sw_drift <- function(rate, JKI = pfm::drift_data_JKI[[applications]][dist_index, crop_group_JKI], RF = drift_percentages_rautmann(distances, applications, formula = formula, - crop_group_RF, widths = water_width/100) + crop_group_RF, widths = as.numeric(set_units(water_width, "m"))) ) names(drift_percentages) <- paste(dist_index, "m") } else { |