Plot long-term summary statistics from annual monthly mean flows

Plots the long-term mean, median, maximum, minimum, and percentiles of annual monthly mean flow values for all months and all data (Long-term) from a daily streamflow data set. Calculates statistics from all values, unless specified. The Maximum-Minimum band can be removed using the include_extremes argument and the percentile bands can be customized using the inner_percentiles and outer_percentiles arguments. Data calculated using the calc_longterm_monthly_stats() function. Returns a list of plots.

plot_longterm_monthly_stats(
  data,
  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  station_number,
  roll_days = 1,
  roll_align = "right",
  water_year_start = 1,
  start_year,
  end_year,
  exclude_years,
  complete_years = FALSE,
  ignore_missing = FALSE,
  include_extremes = TRUE,
  inner_percentiles = c(25, 75),
  outer_percentiles = c(5, 95),
  add_year,
  log_discharge = TRUE,
  include_title = FALSE
)

Arguments

data	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.
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 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.
roll_days	Numeric value of the number of days to apply a rolling mean. Default `1`.
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 to use the first year of the source data.
end_year	Numeric value of the last year to consider for analysis. Leave blank to use the last year of the source data.
exclude_years	Numeric vector of years to exclude from analysis. Leave blank to include all years.
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`.
include_extremes	Logical value to indicate plotting a ribbon with the range of daily minimum and maximum flows. Default `TRUE`.
inner_percentiles	Numeric vector of two percentile values indicating the lower and upper limits of the inner percentiles ribbon for plotting. Default `c(25,75)`, set to `NULL` for no inner ribbon.
outer_percentiles	Numeric vector of two percentile values indicating the lower and upper limits of the outer percentiles ribbon for plotting. Default `c(5,95)`, set to `NULL` for no outer ribbon.
add_year	Numeric value indicating a year of daily flows to add to the daily statistics plot. Leave blank for no years.
log_discharge	Logical value to indicate plotting the discharge axis (Y-axis) on a logarithmic scale. Default `FALSE`.
include_title	Logical value to indicate adding the group/station number to the plot, if provided. Default `FALSE`.

Value

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

Long-term_Monthly_Statistics

a plot that contains long-term flow statistics

Default plots on each object:

Monthly Mean

mean of all annual monthly means for a given month over all years

Monthly Median

median of all annual monthly means for a given month over all years

25-75 Percentiles Range

a ribbon showing the range of data between the monthly 25th and 75th percentiles

5-95 Percentiles Range

a ribbon showing the range of data between the monthly 5th and 95th percentiles

Max-Min Range

a ribbon showing the range of data between the monthly minimum and maximums

Examples

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

# Plot longterm monthly statistics using data argument with defaults
flow_data <- tidyhydat::hy_daily_flows(station_number = "08NM116")
plot_longterm_monthly_stats(data = flow_data,
                            start_year = 1980)

# Plot longterm monthly statistics using station_number argument with defaults
plot_longterm_monthly_stats(station_number = "08NM116",
                            start_year = 1980)
            
# Plot longterm monthly statistics and add a specific year's daily flows                
plot_longterm_monthly_stats(station_number = "08NM116",
                            start_year = 1980,
                            add_year = 1985) 
                              
                            
}
#> $`Long-term_Monthly_Statistics`
#>

Arguments

Value

See also

Examples