Plot annual n-day minimum values, and the day of year and date of occurrence of daily flow values from a daily
streamflow data set. Calculates statistics from all values, unless specified. Data calculated from calc_annual_lowflows()
function. Returns a list of plots.
plot_annual_lowflows(
data,
dates = Date,
values = Value,
groups = STATION_NUMBER,
station_number,
roll_days = c(1, 3, 7, 30),
roll_align = "right",
water_year_start = 1,
start_year,
end_year,
exclude_years,
months = 1:12,
complete_years = FALSE,
ignore_missing = FALSE,
allowed_missing = ifelse(ignore_missing, 100, 0),
include_title = FALSE
)
Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers).
Leave blank or set to NULL
if using station_number
argument.
Name of column in data
that contains dates formatted YYYY-MM-DD. Only required if dates column name is not
'Date' (default). Leave blank or set to NULL
if using station_number
argument.
Name of 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.
Name of 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.
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 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 (1
through 12
) of the start of water year for
analysis. Default 1
.
Numeric value of the first year to consider for analysis. Leave blank or set well before start date (i.e.
1800
) to use from the first year of the source data.
Numeric value of the last year to consider for analysis. Leave blank or set well after end date (i.e.
2100
) to use up to the last year of the source data.
Numeric vector of years to exclude from analysis. Leave blank or set to NULL
to include all years.
Numeric vector of months to include in analysis. For example, 3
for March, 6:8
for Jun-Aug or
c(10:12,1)
for first four months (Oct-Jan) when water_year_start = 10
(Oct). Default summarizes all
months (1:12
).
Logical values indicating whether to include only years with complete data in analysis. 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 those statistics from
time periods with no missing dates will be returned. Default FALSE
.
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 'ignore_missing = FALSE'
then it defaults to 0
(zero missing dates allowed),
if 'ignore_missing = TRUE'
then it defaults to 100
(any missing dates allowed); consistent with
ignore_missing
usage. Supersedes ignore_missing
when used.
Logical value to indicate adding the group/station number to the plot, if provided. Default FALSE
.
A list of ggplot2 objects with the following for each station provided:
ggplot2 object of annual minimums of selected n-day rolling means
ggplot2 object of the day of years of annual minimums of selected n-day rolling means
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {
# Plot annual 1, 3, 7, and 30-day (default) low flow statistics with default alignment
plot_annual_lowflows(station_number = "08NM116")
# Plot annual custom 3 and 7-day low flow statistics with "center" alignment
plot_annual_lowflows(station_number = "08NM116",
roll_days = c(3,7),
roll_align = "center")
}
#> Warning: One or more calculations included missing values and NA's were produced. If desired, filter data for complete years or months, or use the 'ignore_missing' or 'allowed_missing' arguments (if applicable) to ignore or allow some missing values.
#> Warning: One or more calculations included missing values and NA's were produced. If desired, filter data for complete years or months, or use the 'ignore_missing' or 'allowed_missing' arguments (if applicable) to ignore or allow some missing values.
#> $Annual_Low_Flows
#>
#> $Annual_Low_Flows_Dates
#>