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Calculates the long-term and long-term monthly mean, median, maximum, minimum, and percentiles of daily flow values from a streamflow dataset. Calculates the statistics from all daily values from all years, unless specified.
calc_longterm_daily_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_longterm = TRUE,
custom_months,
custom_months_label,
transpose = FALSE,
ignore_missing = FALSE
)A data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers).
Leave blank if using station_number argument.
Column in data that contains dates formatted YYYY-MM-DD. Only required if dates column name is not '
Date' (default). Leave blank if using station_number argument.
Column in data that contains numeric flow values, in units of cubic metres per second.
Only required if values column name is not 'Value' (default). Leave blank if using station_number argument.
Column in data that contains unique identifiers for different data sets, if applicable. Only required if
groups column name is not 'STATION_NUMBER'. Function will automatically group by a column named 'STATION_NUMBER' if present.
Remove the 'STATION_NUMBER' column beforehand to remove this grouping. Leave blank if using station_number argument.
A character string vector of seven digit Water Survey of Canada station numbers (e.g. "08NM116") of
which to extract daily streamflow data from a HYDAT database. Requires tidyhydat package and a HYDAT database.
Leave blank if using data argument.
Numeric vector of percentiles to calculate. Set to NA if none required. Default c(10,90).
Numeric value of the number of days to apply a rolling mean. Default 1.
Character string identifying the direction of the rolling mean from the specified date, either by the first
('left'), last ('right), or middle ('center') day of the rolling n-day group of observations. Default 'right'.
Numeric value indicating the month of the start of the water year for analysis. Default 1.
Numeric value of the first year to consider for analysis. Leave blank to use the first year of the source data.
Numeric value of the last year to consider for analysis. Leave blank to use the last year of the source data.
Numeric vector of years to exclude from analysis. Leave blank to include all years.
Numeric vector of months to include in analysis (e.g.. 6:8 for Jun-Aug). Leave blank to summarize
all months (default 1:12).
Logical values indicating whether to include only years with complete data in analysis. Default FALSE.
Logical value indicating whether to include longterm calculation of all data. Default TRUE.
Numeric vector of months to combine to summarize (ex. 6:8 for Jun-Aug). Adds results to the end of table.
If wanting months that overlap calendar years (ex. Oct-Mar), choose water_year_start that begins before the first
month listed. Leave blank for no custom month summary.
Character string to label custom months. For example, if choosing months 7:9 you may choose
"Summer" or "Jul-Sep". Default "Custom-Months".
Logical value indicating if the results rows and columns are to be switched. Default FALSE.
Logical value indicating whether dates with missing values should be included in the calculation. If
TRUE then a statistic will be calculated regardless of missing dates. If FALSE then only statistics from time periods
with no missing dates will be returned. Default FALSE.
A tibble data frame with the following columns:
month of the year, included 'Long-term' for all months, and 'Custom-Months' if selected
mean of all daily data for a given month and long-term over all years
median of all daily data for a given month and long-term over all years
maximum of all daily data for a given month and long-term over all years
minimum of all daily data for a given month and long-term over all years
each n-th percentile selected for a given month and long-term over all years
annual 10th percentile selected for a given month and long-term over all years
annual 90th percentile selected for a given month and long-term over all years
# NOT RUN {
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {
# Calculate long-term statistics using data argument with defaults
flow_data <- tidyhydat::hy_daily_flows(station_number = "08NM116")
calc_longterm_daily_stats(data = flow_data,
start_year = 1980)
# Calculate long-term statistics using station_number argument with defaults
calc_longterm_daily_stats(station_number = "08NM116",
start_year = 1980)
# Calculate long-term statistics regardless if there is missing data for a given year
calc_longterm_daily_stats(station_number = "08NM116",
ignore_missing = TRUE)
# Calculate long-term statistics for water years starting in October
calc_longterm_daily_stats(station_number = "08NM116",
start_year = 1980,
water_year_start = 10)
# Calculate long-term statistics with custom years
calc_longterm_daily_stats(station_number = "08NM116",
start_year = 1981,
end_year = 2010,
exclude_years = c(1991,1993:1995))
# Calculate long-term statistics for 7-day flows for July-September months only,
# with 25 and 75th percentiles
calc_longterm_daily_stats(station_number = "08NM116",
roll_days = 7,
months = 7:9,
percentiles = c(25,75),
ignore_missing = TRUE,
include_longterm = FALSE) # removes the Long-term numbers
# Calculate long-term statistics and add custom stats for July-September
calc_longterm_daily_stats(station_number = "08NM116",
start_year = 1980,
custom_months = 7:9,
custom_months_label = "Summer")
}
# }
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