Get the 5km grid reference

This function returns the 5km grid reference for a higher precision grid reference.

pentad(x)

# S3 method for gridref
pentad(grid_reference)

Arguments

grid_reference	A Great British or Irish grid reference character string with class gridref.

Value

The grid reference at 5km resolution.

Details

It can check either British or Irish grid references up to 10 figure (1m precision), including tetrads (2000m precision).

REST API

A REST API endpoint is available once a Plumber router has been created and can be requested by adding _api to the end of the function.

The API returns "" instead of NULL so that it may be used with the dplyr::mutate function. Wrap the API call with dplyr::na_if to convert "" to NA.

suppressPackageStartupMessages({
  library(store)
  suppressWarnings({
    library(plumber)
  })
})
pr("../R/gridref_api.R") %>%
  pr_run(port = 8000)

See also

Other grid reference functions: easting(), gridsquare_geometry(), hectad(), hectare(), monad(), northing(), precision(), projection(), tetrad()

Examples

 suppressPackageStartupMessages({
   library(store)
   suppressWarnings({
     library(dplyr)
     library(janitor)
   })
 })

 grid_references <- nbn_demonstration_dataset %>%
   clean_names() %>%
   slice_tail(n = 15) %>%
   select(grid_reference) %>%
   mutate(grid_reference = as_gridref(grid_reference))


# add five_km column
suppressPackageStartupMessages({
  suppressWarnings({
    library(dplyr)
  })
})

grid_references %>%
  rowwise() %>%
  mutate(five_km = pentad(grid_reference))
#> # A tibble: 15 x 2
#> # Rowwise: 
#>    grid_reference five_km
#>    <gridref>      <chr>  
#>  1 TL2384         TL28SW 
#>  2 TL232839       TL28SW 
#>  3 TL2385         TL28NW 
#>  4 TL231840       TL28SW 
#>  5 TL232839       TL28SW 
#>  6 TL23248346     TL28SW 
#>  7 TL23568493     TL28SW 
#>  8 TL23448505     TL28NW 
#>  9 TL23128324     TL28SW 
#> 10 TL234850       TL28NW 
#> 11 TL234846       TL28SW 
#> 12 TL232839       TL28SW 
#> 13 TL231841       TL28SW 
#> 14 TL226846       TL28SW 
#> 15 TL2384         TL28SW