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Convert BNG References

bng_to_xy.Rd

Create British National Grid references from coordinates at a specific resolution or convert grid reference objects to coordinates at a grid position.

Usage

bng_to_xy(
  bng_ref,
  position = c("lower-left", "upper-left", "upper-right", "lower-right", "centre"),
  ...
)

xy_to_bng(...)

# S3 method for numeric
xy_to_bng(easting, northing, resolution, ...)

# S3 method for matrix
xy_to_bng(x, resolution, ...)

# S3 method for data.frame
xy_to_bng(df, cols = c("eastings", "northings"), resolution, ...)

Arguments

bng_ref

vector of type BNGReference objects

position

character indicating which point location of the BNG grid square is returned. Default is the lower-left corner.

...

additional parameters, not currently used

easting

numeric vector of coordinates

northing

numeric vector of coordinates

resolution

target BNG grid resolution. Can be specified as a numeric or character vector

x

two column matrix of eastings and northings

df

data.frame with columns of coordinates to convert

cols

column names or indices within df holding coordinates

Value

  • xy_to_bng: vector of BNGReference objects

  • bng_to_xy: two-column matrix of eastings and northings

Details

Coordinates must be in British National Grid projection (EPSG:27700) using eastings and northings in meters. These functions do not support coordinate transformations.

Examples

bng_to_xy(as_bng_reference("SU"), "lower-left")
#>       [,1]  [,2]
#> [1,] 4e+05 1e+05

bng_to_xy(as_bng_reference("SU 3 1"), "lower-left")
#>        [,1]   [,2]
#> [1,] 430000 110000

bng_to_xy(as_bng_reference("SU 3 1 NE"), "centre")
#>        [,1]   [,2]
#> [1,] 437500 117500

bng_to_xy(as_bng_reference("SU 37289 15541"), "centre")
#>          [,1]     [,2]
#> [1,] 437289.5 115541.5

xy_to_bng(437289, 115541, "100km")
#> <BNGReference[1] with Resolution=100km>
#> [1] <SU>

xy_to_bng(437289, 115541, "10km")
#> <BNGReference[1] with Resolution=10km>
#> [1] <SU 3 1>

xy_to_bng(437289, 115541, "5km")
#> <BNGReference[1] with Resolution=5km>
#> [1] <SU 3 1 NE>

xy_to_bng(437289, 115541, 1)
#> <BNGReference[1] with Resolution=1m>
#> [1] <SU 37289 15541>
  
# example code

# example code