Get the northing of a grid reference

This function returns the grid reference's northing in metres.

northing(x, ...)

# S3 method for gridref
northing(grid_reference, centre = FALSE)

Arguments

grid_reference	A Great British or Irish grid reference character string with class gridref.
centre	Should the northing be for the lower left hand corner (default FALSE) or the centre point (TRUE).

Value

The northing of grid reference in metres.

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(), pentad(), 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 northing column for the centre point
suppressPackageStartupMessages({
  suppressWarnings({
    library(dplyr)
  })
})

grid_references %>%
  rowwise() %>%
  mutate(northing_corner = northing(grid_reference),
         northing_centre = northing(grid_reference, centre = TRUE))
#> # A tibble: 15 x 3
#> # Rowwise: 
#>    grid_reference northing_corner northing_centre
#>    <gridref>                <dbl>           <dbl>
#>  1 TL2384                  284000          284500
#>  2 TL232839                283900          283950
#>  3 TL2385                  285000          285500
#>  4 TL231840                284000          284050
#>  5 TL232839                283900          283950
#>  6 TL23248346              283460          283465
#>  7 TL23568493              284930          284935
#>  8 TL23448505              285050          285055
#>  9 TL23128324              283240          283245
#> 10 TL234850                285000          285050
#> 11 TL234846                284600          284650
#> 12 TL232839                283900          283950
#> 13 TL231841                284100          284150
#> 14 TL226846                284600          284650
#> 15 TL2384                  284000          284500