Calculates means, medians, maximums, minimums, and percentiles for each month of all years of flow values from a daily streamflow data set. Calculates statistics from all values, unless specified. Returns a tibble with statistics.
calc_monthly_stats( data, dates = Date, values = Value, groups = STATION_NUMBER, station_number, percentiles = c(10, 90), roll_days = 1, roll_align = "right", water_year_start = 1, start_year, end_year, exclude_years, months = 1:12, transpose = FALSE, spread = FALSE, ignore_missing = FALSE )
data  Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers).
Leave blank if using 

dates  Name of column in 
values  Name of column in 
groups  Name of column in 
station_number  Character string vector of seven digit Water Survey of Canada station numbers (e.g. 
percentiles  Numeric vector of percentiles to calculate. Set to 
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 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. 
months  Numeric vector of months to include in analysis (e.g. 
transpose  Logical value indicating if each month statistic should be individual rows. Default 
spread  Logical value indicating if each month statistic should be the column name. Default 
ignore_missing  Logical value indicating whether dates with missing values should be included in the calculation. If

A tibble data frame with the following columns:
calendar or water year selected
month of the year
mean of all daily flows for a given month and year
median of all daily flows for a given month and year
maximum of all daily flows for a given month and year
minimum of all daily flows for a given month and year
each nth percentile selected for a given month and year
10th percentile of all daily flows for a given month and year
90th percentile of all daily flows for a given month and year
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat()) if (file.exists(tidyhydat::hy_downloaded_db())) { # Calculate statistics using a data frame and data argument with defaults flow_data < tidyhydat::hy_daily_flows(station_number = "08NM116") calc_monthly_stats(data = flow_data, start_year = 1980) # Calculate statistics using station_number argument with defaults calc_monthly_stats(station_number = "08NM116", start_year = 1980) # Calculate statistics regardless if there is missing data for a given year calc_monthly_stats(station_number = "08NM116", ignore_missing = TRUE) # Calculate statistics for water years starting in October calc_monthly_stats(station_number = "08NM116", start_year = 1980, water_year_start = 10) # Calculate statistics with custom years calc_monthly_stats(station_number = "08NM116", start_year = 1981, end_year = 2010, exclude_years = c(1991,1993:1995)) # Calculate statistics for 7day flows, with 25 and 75th percentiles calc_monthly_stats(station_number = "08NM116", roll_days = 7, percentiles = c(25,75), ignore_missing = TRUE) }#> Warning: One or more calculations included missing values and NA's were produced. Some months in some years have no data to summarize.#> Warning: One or more calculations included missing values and NA's were produced. Filter data for complete years or months, or use to ignore_missing = TRUE to ignore missing values.#> Warning: One or more calculations included missing values and NA's were produced. Some months in some years have no data to summarize.#> # A tibble: 828 x 9 #> STATION_NUMBER Year Month Mean Median Maximum Minimum P25 P75 #> <chr> <dbl> <fct> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> #> 1 08NM116 1949 Jan NA NA NA NA NA NA #> 2 08NM116 1949 Feb NA NA NA NA NA NA #> 3 08NM116 1949 Mar NA NA NA NA NA NA #> 4 08NM116 1949 Apr 7.27 6.64 13.6 1.93 3.51 11.2 #> 5 08NM116 1949 May 26.2 27.8 41.1 13.1 15.1 34.2 #> 6 08NM116 1949 Jun 9.63 7.45 20.8 3.59 4.08 14.9 #> 7 08NM116 1949 Jul 1.93 1.56 4.29 0.950 1.24 2.00 #> 8 08NM116 1949 Aug 1.25 1.23 1.68 0.882 1.09 1.35 #> 9 08NM116 1949 Sep 1.37 1.39 1.97 0.838 1.01 1.64 #> 10 08NM116 1949 Oct NA NA NA NA NA NA #> # ... with 818 more rows