R/screen_flow_data.R
screen_flow_data.RdCalculates 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 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.
Name of column in data that contains symbols. Only required if symbols column name is not
'Symbol' (default). Leave blank or set to NULL 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 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 value indicating whether to transpose rows and columns of results. Default FALSE.
Logical. Include columns of counts of symbol categories from the symbols column.
A tibble data frame with the following columns:
calendar or water year selected
number of days per year
number of days per year with flow data
number of days per year with no flow data
number of days with no symbol category, if include_symbol=TRUE
number of days with a specific symbol category (x) from symbols column, if include_symbol=TRUE
annual maximum of all daily flows for a given year
annual mean of all daily flows for a given year
annual median of all daily flows for a given year
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):
number of Jan days per year with no flow data
number of Feb days per year with no flow data
number of Mar days per year with no flow data
number of Apr days per year with no flow data
number of May days per year with no flow data
number of Jun days per year with no flow data
number of Jul days per year with no flow data
number of Aug days per year with no flow data
number of Sep days per year with no flow data
number of Oct days per year with no flow data
number of Nov days per year with no flow data
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 7-day flows for July-September months only
screen_flow_data(station_number = "08NM116",
roll_days = 7,
months = 7:9)
}
#> # A tibble: 72 × 16
#> STATION_…¹ Year n_days n_Q n_mis…² E_Sym…³ No_Sy…⁴ A_Sym…⁵ Minimum Maximum
#> <chr> <dbl> <int> <int> <int> <int> <int> <int> <dbl> <dbl>
#> 1 08NM116 1949 92 92 0 5 87 0 0.838 4.29
#> 2 08NM116 1950 92 92 0 0 92 0 0.714 16.6
#> 3 08NM116 1951 92 92 0 0 92 0 0.629 8.80
#> 4 08NM116 1952 92 92 0 0 92 0 1.11 12.9
#> 5 08NM116 1953 92 92 0 0 92 0 0.821 24.1
#> 6 08NM116 1954 92 92 0 0 92 0 1.98 30.5
#> 7 08NM116 1955 92 92 0 0 92 0 0.396 19.9
#> 8 08NM116 1956 92 92 0 0 92 0 0.784 8.21
#> 9 08NM116 1957 92 92 0 0 92 0 0.916 6.23
#> 10 08NM116 1958 92 92 0 0 92 0 0.578 5.51
#> # … with 62 more rows, 6 more variables: Mean <dbl>, Median <dbl>,
#> # StandardDeviation <dbl>, Jul_missing_Q <int>, Aug_missing_Q <int>,
#> # Sep_missing_Q <int>, and abbreviated variable names ¹STATION_NUMBER,
#> # ²n_missing_Q, ³E_Symbol, ⁴No_Symbol, ⁵A_Symbol