Plot annual high and low flows for a specific year

Source: R/plot_annual_extremes_year.R

Plots an annual hydrograph for a specific year with the values and timing of annual n-day low and high flows. The 'normal' range of percentiles also plotted for reference and are calculated from only years of complete data. Shows the values and dates of max/mins for a specific year from the calc_annual_extremes() and plot_annual_extremes() functions. Can remove either low or high flows using plot_min = FALSE() or plot_max = FALSE(), respectively. Returns a list of plots.

plot_annual_extremes_year(
  data,
  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  station_number,
  year_to_plot = NA,
  roll_days = 1,
  roll_days_min = NA,
  roll_days_max = NA,
  roll_align = "right",
  water_year_start = 1,
  start_year,
  end_year,
  exclude_years,
  months = 1:12,
  months_min = NA,
  months_max = NA,
  log_discharge = TRUE,
  log_ticks = FALSE,
  include_title = FALSE,
  plot_normal_percentiles = TRUE,
  normal_percentiles = c(25, 75),
  plot_min = TRUE,
  plot_max = TRUE,
  complete_years = FALSE,
  ignore_missing = FALSE,
  allowed_missing = ifelse(ignore_missing, 100, 0)
)

Arguments

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 NULL if using station_number argument.

dates

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.

values

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.

groups

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.

station_number

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.

year_to_plot

Numeric value indicating the year/water year to plot flow data with normal category colours. Default NA.

roll_days

Numeric value of the number of days to apply a rolling mean. Default 1.

roll_days_min

Numeric value of the number of days to apply a rolling mean for low flows. Will override 'roll_days' argument for low flows. Default NA.

roll_days_max

Numeric value of the number of days to apply a rolling mean for high flows. Will override 'roll_days' argument for high flows. Default NA.

roll_align

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'.

water_year_start

Numeric value indicating the month (1 through 12) of the start of water year for analysis. Default 1.

start_year

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.

end_year

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.

exclude_years

Numeric vector of years to exclude from analysis. Leave blank or set to NULL to include all years.

months

Numeric vector of specific months to plot. For example, 3 for March, 6:8 for Jun-Aug. Will be overridden for low or high flow statistics if months_min or months_max set, but will still define the date limits on the x-axis. Default plots all months (1:12).

months_min

Numeric vector of specified months for window of low flows (3 for March, 6:8 for Jun-Aug). Will override 'months' argument for low flows. Default NA.

months_max

Numeric vector of specified months for window of high flows (3 for March, 6:8 for Jun-Aug). Will override 'months' argument for high flows. Default NA.

log_discharge

Logical value to indicate plotting the discharge axis (Y-axis) on a logarithmic scale. Default FALSE.

log_ticks

Logical value to indicate plotting logarithmic scale ticks when log_discharge = TRUE. Ticks will not appear when log_discharge = FALSE. Default to TRUE when log_discharge = TRUE.

include_title

Logical value to indicate adding the group/station number to the plot, if provided. Default FALSE.

plot_normal_percentiles

Logical value indicating whether to plot the normal percentiles ribbon. Default TRUE.

normal_percentiles

Numeric vector of two values, lower and upper percentiles, respectively indicating the limits of the normal range. Default c(25,75).

plot_min

Logical value indicating whether to plot annual low flows. Default TRUE.

plot_max

Logical value indicating whether to plot annual high flows. Default TRUE.

complete_years

Logical values indicating whether to include only years with complete data in analysis. Default FALSE.

ignore_missing

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.

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 '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.

Value

A list of ggplot2 objects with the following for each station provided:

Annual_Extremes_Year

a plot that contains the an annual hydrograph and identified low and high flow periods

Examples

# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {

# Plot the year 2000 with the annual maximum and minimums       
plot_annual_extremes_year(station_number = "08NM116",
                          roll_days_max = 3,
                          roll_days_min = 7,
                          year_to_plot = 2001)
                 
}
#> 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_Extremes_Year
#> Warning: Transformation introduced infinite values in continuous y-axis
#> Warning: Transformation introduced infinite values in continuous y-axis

#>