View source: R/screen_flow_data.R
screen_flow_data  R Documentation 
Calculates means, medians, maximums, minimums, standard deviations of annual flows and data availability and missing data statistics, and symbol counts (if column exists) for each year and month of each year. Calculates the statistics from all daily discharge values from all years, unless specified. Returns a tibble with statistics.
screen_flow_data(
data,
dates = Date,
values = Value,
groups = STATION_NUMBER,
symbols = "Symbol",
station_number,
roll_days = 1,
roll_align = "right",
water_year_start = 1,
start_year,
end_year,
months = 1:12,
transpose = FALSE,
include_symbols = TRUE
)
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 
dates 
Name of column in 
values 
Name of column in 
groups 
Name of column in 
symbols 
Name of column in 
station_number 
Character string vector of seven digit Water Survey of Canada station numbers (e.g. 
roll_days 
Numeric value of the number of days to apply a rolling mean. Default 
roll_align 
Character string identifying the direction of the rolling mean from the specified date, either by the first
( 
water_year_start 
Numeric value indicating the month ( 
start_year 
Numeric value of the first year to consider for analysis. Leave blank or set well before start date (i.e.

end_year 
Numeric value of the last year to consider for analysis. Leave blank or set well after end date (i.e.

months 
Numeric vector of months to include in analysis. For example, 
transpose 
Logical value indicating whether to transpose rows and columns of results. Default 
include_symbols 
Logical. Include columns of counts of symbol categories from the symbols column. 
A tibble data frame with the following columns:
Year 
calendar or water year selected 
n_days 
number of days per year 
n_Q 
number of days per year with flow data 
n_missing_Q 
number of days per year with no flow data 
No_Symbol 
number of days with no symbol category, if include_symbol=TRUE 
x_Symbol 
number of days with a specific symbol category (x) from symbols column, if include_symbol=TRUE 
Maximum 
annual maximum of all daily flows for a given year 
Mean 
annual mean of all daily flows for a given year 
Median 
annual median of all daily flows for a given year 
StandardDeviation 
annual 1 standard deviation of all daily flows for a given year 
and the following monthly missing columns (order will depend on water_year_month):
Jan_missing_Q 
number of Jan days per year with no flow data 
Feb_missing_Q 
number of Feb days per year with no flow data 
Mar_missing_Q 
number of Mar days per year with no flow data 
Apr_missing_Q 
number of Apr days per year with no flow data 
May_missing_Q 
number of May days per year with no flow data 
Jun_missing_Q 
number of Jun days per year with no flow data 
Jul_missing_Q 
number of Jul days per year with no flow data 
Aug_missing_Q 
number of Aug days per year with no flow data 
Sep_missing_Q 
number of Sep days per year with no flow data 
Oct_missing_Q 
number of Oct days per year with no flow data 
Nov_missing_Q 
number of Nov days per year with no flow data 
Dec_missing_Q 
number of Dec days per year with no flow data 
Transposing data creates a column of "Statistics" and subsequent columns for each year selected.
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {
# Calculate screening statistics using data frame and data argument with defaults
flow_data < tidyhydat::hy_daily_flows(station_number = "08NM116")
screen_flow_data(data = flow_data)
# Calculate screening statistics using station_number argument with defaults
screen_flow_data(station_number = "08NM116")
# Calculate screening statistics for water years starting in October
screen_flow_data(station_number = "08NM116",
water_year_start = 9)
# Calculate screening statistics for 7day flows for JulySeptember months only
screen_flow_data(station_number = "08NM116",
roll_days = 7,
months = 7:9)
}
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