View source: R/calc_longterm_mean.R
calc_longterm_mean  R Documentation 
Calculates the longterm mean annual discharge (MAD) from a daily streamflow data set. Calculates statistics from all values, unless specified. Returns a tibble with statistics.
calc_longterm_mean(
data,
dates = Date,
values = Value,
groups = STATION_NUMBER,
station_number,
roll_days = 1,
roll_align = "right",
water_year_start = 1,
start_year,
end_year,
exclude_years,
complete_years = FALSE,
months = 1:12,
percent_MAD,
transpose = FALSE
)
data 
Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers).
Leave blank or set to 
dates 
Name of column in 
values 
Name of column in 
groups 
Name of column in 
station_number 
Character string vector of seven digit Water Survey of Canada station numbers (e.g. 
roll_days 
Numeric value of the number of days to apply a rolling mean. Default 
roll_align 
Character string identifying the direction of the rolling mean from the specified date, either by the first
( 
water_year_start 
Numeric value indicating the month ( 
start_year 
Numeric value of the first year to consider for analysis. Leave blank or set well before start date (i.e.

end_year 
Numeric value of the last year to consider for analysis. Leave blank or set well after end date (i.e.

exclude_years 
Numeric vector of years to exclude from analysis. Leave blank or set to 
complete_years 
Logical values indicating whether to include only years with complete data in analysis. Default 
months 
Numeric vector of months to include in analysis. For example, 
percent_MAD 
Numeric vector of percents of longterm mean annual discharge to add to the table (ex. 
transpose 
Logical value indicating whether to transpose rows and columns of results. Default 
A tibble data frame of numeric values of a longterm mean (and percent of longterm mean if selected) of selected years and months.
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {
# Calculate the longterm mean annual discharge (MAD) using only years with no missing data
calc_longterm_mean(station_number = "08NM116",
complete_years = TRUE)
# Calculate the longterm MAD and 5, 10 and 20percent MADs using only years with no missing data
calc_longterm_mean(station_number = "08NM116",
complete_years = TRUE,
percent_MAD = c(5,10,20))
}
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