Filter Yarra River water quality data — filter_yarra

This helper function returns a filtered version of the yarra_wq dataset (included in the yarraWQ package). It lets you select which water quality parameter to look at (for example "pH", "temperature", "turbidity"), and optionally limit to a single monitoring site.

Usage

filter_yarra_data(data, parameter_name, site_name = NULL)

Arguments

data: A data frame with the same columns as yarra_wq. Typically you will just pass yarra_wq.
parameter_name: A string giving the parameter to filter on, for example "pH", "temperature", "turbidity", "dissolved_oxygen". This will be matched to the parameter column.
site_name: Optional. A string giving the site to filter on (matching the name column, e.g. "YARRA @ CHANDLER HWY"). If NULL (the default), all sites are included.

Value

A tibble/data.frame containing only rows that match the requested parameter and (if provided) site. If nothing matches, the returned tibble will have 0 rows.

Details

This is useful because both the plotting function (plot_yarra_metric()) and the Shiny app do the same type of filtering. Putting this logic in one place avoids repeating the same code in multiple places.

Examples

# Keep only pH measurements (all sites):
# filtered <- filter_yarra_data(yarra_wq, parameter_name = "pH")

# Keep only pH at one specific site:
# filtered_site <- filter_yarra_data(
#   yarra_wq,
#   parameter_name = "pH",
#   site_name = "YARRA @ CHANDLER HWY"
# )