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Process Polling Place Coordinates

Source: R/process_coords.R
process_coords.Rd

Updates missing or invalid coordinate data for polling places in the "Polling place" dataset from Australian federal elections. This helper function fills in missing (NA) or zero-valued latitude and longitude coordinates by matching PollingPlaceID with an internal coordinate dataset (coords) stored in the scgElectionsAU package namespace. The function processes data for any specified election year, ensuring alignment with known polling place locations.

Usage

process_coords(data, event)

Arguments

data

A data frame containing polling place data for a single election event. Must include:

  • event (the election event, e.g., "2004 Federal Election", "2010 Federal Election")

  • PollingPlaceID (unique identifier for polling places)

  • Latitude (latitude coordinate, potentially NA or 0)

  • Longitude (longitude coordinate, potentially NA or 0)

A date column is typically present as mandatory metadata.

event

A character string specifying the election event (e.g., "2004 Federal Election", "2010 Federal Election"). Used for logging purposes only; processing occurs for all years.

Value

A data frame identical to the input, with updated columns:

  • Latitude (updated with non-NA, non-zero values from the internal coords dataset where matches are found)

  • Longitude (updated with non-NA, non-zero values from the internal coords dataset where matches are found)

Unmatched or already valid coordinates remain unchanged.

Details

This function processes polling place coordinates by:

  1. Retrieving internal data: Accesses the coords dataset from the scgElectionsAU package namespace, which contains known PollingPlaceID, Latitude, and Longitude values.

  2. Matching polling places: Uses PollingPlaceID to match rows in the input data with the internal coords dataset.

  3. Updating coordinates: Replaces NA or zero values in Latitude and Longitude with corresponding values from coords where matches exist.

  4. Logging: Outputs a message indicating the election year being processed, though processing applies universally regardless of year.

The function assumes the input data frame contains the required columns (event, PollingPlaceID, Latitude, and Longitude) as sourced from the AEC "Polling place" dataset, and that the internal coords dataset is available and correctly formatted within the package namespace.

Examples

# Sample data with missing coordinates
data_2010 <- data.frame(
  date = "2010-08-21",
  event = "2010 Federal Election",
  PollingPlaceID = c(93925.0, 11877.0),
  Latitude = c(NA, 0),
  Longitude = c(0, NA)
)
process_coords(data_2010, "2010 Federal Election")
#> Filling in missing coordinates for `2010 Federal Election` data, where possible.
#>         date                 event PollingPlaceID  Latitude Longitude
#> 1 2010-08-21 2010 Federal Election          93925 -35.23895  149.0691
#> 2 2010-08-21 2010 Federal Election          11877 -35.43119  149.0830

# Sample data with some valid coordinates
data_2013 <- data.frame(
  date = "2013-09-07",
  event = "2013 Federal Election",
  PollingPlaceID = c(93925.0, 11877.0),
  Latitude = c(-37.81, -33.87),
  Longitude = c(144.96, 151.21)
)
process_coords(data_2013, "2013 Federal Election")
#> Filling in missing coordinates for `2013 Federal Election` data, where possible.
#>         date                 event PollingPlaceID Latitude Longitude
#> 1 2013-09-07 2013 Federal Election          93925   -37.81    144.96
#> 2 2013-09-07 2013 Federal Election          11877   -33.87    151.21