View source: R/calc_annual_stats.R
calc_annual_stats  R Documentation 
Calculates means, medians, maximums, minimums, and percentiles for each year from all years of a daily streamflow data set. Calculates statistics from all values, unless specified. Returns a tibble with statistics.
calc_annual_stats(
data,
dates = Date,
values = Value,
groups = STATION_NUMBER,
station_number,
roll_days = 1,
roll_align = "right",
percentiles = c(10, 90),
water_year_start = 1,
start_year,
end_year,
exclude_years,
months = 1:12,
transpose = FALSE,
complete_years = FALSE,
ignore_missing = FALSE,
allowed_missing = ifelse(ignore_missing, 100, 0)
)
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
( 
percentiles 
Numeric vector of percentiles to calculate. Set to 
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 
months 
Numeric vector of months to include in analysis. For example, 
transpose 
Logical value indicating whether to transpose rows and columns of results. Default 
complete_years 
Logical values indicating whether to include only years with complete data in analysis. Default 
ignore_missing 
Logical value indicating whether dates with missing values should be included in the calculation. If

allowed_missing 
Numeric value between 0 and 100 indicating the percentage of missing dates allowed to be
included to calculate a statistic (0 to 100 percent). If 
A tibble data frame with the following columns:
Year 
calendar or water year selected 
Mean 
annual mean of all daily flows for a given year 
Median 
annual median of all daily flows for a given year 
Maximum 
annual maximum of all daily flows for a given year 
Minimum 
annual minimum of all daily flows for a given year 
P'n' 
each annual nth percentile selected of all daily flows 
Default percentile columns:
P10 
annual 10th percentile of all daily flows for a given year 
P90 
annual 90th percentile of all daily flows for a given year 
Transposing data creates a column of "Statistics" and subsequent columns for each year selected.
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {
# Calculate annual statistics from a data frame using the data argument
flow_data < tidyhydat::hy_daily_flows(station_number = "08NM116")
calc_annual_stats(data = flow_data)
# Calculate annual statistics using station_number argument
calc_annual_stats(station_number = "08NM116")
# Calculate annual statistics regardless if there
# is missing data for a given year
calc_annual_stats(station_number = "08NM116",
ignore_missing = TRUE)
# Calculate annual statistics for water years starting in October
calc_annual_stats(station_number = "08NM116",
water_year_start = 10)
# Calculate annual statistics for 7day flows for JulySeptember
# months only, with 25 and 75th percentiles
calc_annual_stats(station_number = "08NM116",
roll_days = 7,
months = 7:9,
percentiles = c(25,75))
}
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