improve document of flood division

NAMESPACE

@@ -90,6 +90,7 @@ export(celsius.to.fahrenheit)
 export(celsius.to.kelvin)
 export(convert_temperature)
 export(cv_coef)
+export(ddays)
 export(deg2rad)
 export(detect_flood_events)
 export(detect_groups)

R/flood_divide.R

@@ -12,26 +12,31 @@ get_event_info <- function(date, Q, extend = ddays(5)) {
 }
 
 #' @param gap_max distance smaller than gap_max is considered as a same group
-#' 
+#'
 #' @rdname flood_divide
-#' @export 
+#' @export
 detect_groups <- function(df, inds, gap_max = 5, extend = ddays(5)) {
   grps <- cumsum(c(0, diff(inds) > gap_max)) # 分组
   info <- cbind(group = grps, df[inds, ]) # 分组
   info[, get_event_info(date, Q, extend), group]
 }
 
 #' detect_flood_events
+#'
 #' @param Q_min minimum discharge to detect flood events
 #' @param Q_peak peak discharge to detect flood events
-#' 
+#'
+#' @param gap_max Default `5`. if `index gap > gap_max`, events will be regarded as two.
+#' If Q is hourly, gap_max can be set `5*24`.
+#' @param extend Default `ddays(5)`. Extend `nday` in the left and right of a event
+#'
 #' @rdname flood_divide
 #' @export
-detect_flood_events <- function(date, Q, Q_min = 2, Q_peak = 10, gap_max = 5) {
+detect_flood_events <- function(date, Q, Q_min = 2, Q_peak = 10, gap_max = 5, extend = ddays(5)) {
   df <- data.table(date, Q)
   inds <- df[, which(Q > Q_min)] #
 
-  info_group <- detect_groups(df, inds, gap_max) %>%
+  info_group <- detect_groups(df, inds, gap_max, extend) %>%
     .[Q_max > Q_peak, ]
 
   ## 数据压缩
@@ -41,7 +46,7 @@ detect_flood_events <- function(date, Q, Q_min = 2, Q_peak = 10, gap_max = 5) {
     lgl[date >= info$date_beg & date <= info$date_end] <- TRUE
   }
 
-  # 由于扩展了5天，这里对洪水事件重新进行编号
+  # 由于已经扩展了5天，这里对洪水事件重新进行编号，不需要二次扩展
   inds <- which(lgl)
   info_group <- detect_groups(df, inds, gap_max, extend = 0)
   info_group
@@ -51,12 +56,12 @@ detect_flood_events <- function(date, Q, Q_min = 2, Q_peak = 10, gap_max = 5) {
 #' flood_divide
 #' @param df A data.table with date and Q columns
 #' @param ... parameters passed to [detect_flood_events()]
-#' @export 
+#' @export
 flood_divide <- function(df, ...) {
   date <- df$date
   if ("time" %in% names(df)) date <- df$time
   df <- df[order(date)]
-  info_group <- detect_flood_events(date, df$Q, ...)
+  detect_flood_events(date, df$Q, ...) # info_group
 }
 
 #' @rdname flood_divide

R/hydroTools-package.R

@@ -13,6 +13,10 @@
 ## usethis namespace: end
 NULL
 
+#' @importFrom lubridate ddays
+#' @export
+lubridate::ddays
+
 .onLoad <- function(libname, pkgname) {
   options(rmarkdown.html_vignette.check_title = FALSE)