View source: R/calc_longterm_monthly_stats.R
calc_longterm_monthly_stats  R Documentation 
Calculates the longterm mean, median, maximum, minimum, and percentiles of annual monthly mean flow values for all months and all data (Longterm) from a daily streamflow data set. Calculates statistics from all values, unless specified. Returns a tibble with statistics.
calc_longterm_monthly_stats(
data,
dates = Date,
values = Value,
groups = STATION_NUMBER,
station_number,
percentiles = c(10, 90),
roll_days = 1,
roll_align = "right",
water_year_start = 1,
start_year,
end_year,
exclude_years,
months = 1:12,
complete_years = FALSE,
include_annual = TRUE,
custom_months,
custom_months_label,
transpose = FALSE,
ignore_missing = 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. 
percentiles 
Numeric vector of percentiles to calculate. Set to 
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 
months 
Numeric vector of months to include in analysis. For example, 
complete_years 
Logical values indicating whether to include only years with complete data in analysis. Default 
include_annual 
Logical value indicating whether to include annual calculation of all months. Default 
custom_months 
Numeric vector of months to combine to summarize (ex. 
custom_months_label 
Character string to label custom months. For example, if 
transpose 
Logical value indicating whether to transpose rows and columns of results. Default 
ignore_missing 
Logical value indicating whether dates with missing values should be included in the calculation. If

A tibble data frame with the following columns:
Month 
month of the year, included 'Annual' for all months, and 'CustomMonths' if selected 
Mean 
mean of all annual monthly means for a given month over all years 
Median 
median of all annual monthly means for a given month over all years 
Maximum 
maximum of all annual monthly means for a given month over all years 
Minimum 
minimum of all annual monthly means for a given month over all years 
P'n' 
each nth percentile selected for annual monthly means for a given month over all years 
Default percentile columns:
P10 
annual 10th percentile selected for annual monthly means for a given month over all years 
P90 
annual 90th percentile selected for annual monthly means for a given month over all years 
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 longterm monthly statistics using data argument with defaults
flow_data < tidyhydat::hy_daily_flows(station_number = "08NM116")
calc_longterm_monthly_stats(data = flow_data,
start_year = 1980)
# Calculate longterm monthly statistics using station_number argument with defaults
calc_longterm_monthly_stats(station_number = "08NM116",
start_year = 1980)
# Calculate longterm monthly statistics regardless if there is missing data for a given year
calc_longterm_monthly_stats(station_number = "08NM116",
ignore_missing = TRUE)
# Calculate longterm monthly statistics and add custom stats for JulySeptember
calc_longterm_monthly_stats(station_number = "08NM116",
start_year = 1980,
custom_months = 7:9,
custom_months_label = "Summer")
}
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