Plot a daily streamflow data set

Source: R/plot_flow_data.R

Plot the daily mean flow values from a streamflow data set. Plots daily discharge values from all years, unless specified. Can choose specific dates to start and end plotting. Can choose to plot out each year separately. Multiple groups/stations can be plotted if provided with the groups argument. Returns a list of plots.

plot_flow_data(
  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,
  months = 1:12,
  start_date,
  end_date,
  log_discharge = FALSE,
  log_ticks = ifelse(log_discharge, TRUE, FALSE),
  plot_by_year = FALSE,
  one_plot = FALSE,
  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 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.

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 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 months to include in plotting 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 plots all months (1:12).

start_date

Date (YYYY-MM-DD) of first date to consider for plotting. Leave blank if all years are required.

end_date

Date (YYYY-MM-DD) of last date to consider for plotting. Leave blank if all years are required.

log_discharge

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

log_ticks

Logical value to indicate plotting logarithmic scale ticks when using a log-scale discharge axis. Default to FALSE when log_discharge = FALSE and TRUE when log_discharge = TRUE.

plot_by_year

Logical value to indicate whether to plot each year of data individually. Default FALSE.

one_plot

Logical value to indicate whether to plot all groups/stations on one plot. Default FALSE.

include_title

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

Value

A ggplot2 object of daily flows from flow_data or HYDAT flow data provided

Examples

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

# Plot data from a data frame and data argument
flow_data <- tidyhydat::hy_daily_flows(station_number = "08NM116")
plot_flow_data(data = flow_data)

# Plot data directly from HYDAT
plot_flow_data(station_number = "08NM116")

# Plot statistics with custom years
plot_flow_data(station_number = "08NM116",
               start_year = 1981,
               end_year = 2010,
               exclude_years = c(1991,1993:1995))
                 
# Plot data multiple groups on one plot
plot_flow_data(station_number = c("08NM241", "08NM242"),
               one_plot = TRUE) 
               
# Plot data between specific dates
plot_flow_data(station_number = "08NM116",
               start_date = "1990-01-01",
               end_date = "1990-06-01")
               
}
#> Note: Did not plot 3394 missing or excluded values between 1949-01-01 and 2020-12-31.
#> Note: Did not plot 3394 missing or excluded values between 1949-01-01 and 2020-12-31.
#> Note: Did not plot 1460 missing or excluded values between 1981-01-01 and 2010-12-31.
#> Note: Did not plot 1057 missing or excluded values between 1983-01-01 and 2019-12-31.
#> $Daily_Flows

#>