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Generate INSPIRE IDs

Source: R/inspire_id_from_coords.R, R/inspire_id_to_coords.R
inspire_id_coords.Rd

Given pairs of coordinates, generates their INSPIRE grid representation. Given INSPIRE identifiers, can also extract the X and Y coordinates.

An INSPIRE ID contains information about the CRS, cell size and the ETRS89-LAEA coordinates of the lower-left corner of the grid cell in its format.

CRS3035{cellsize}mN{y}E{x} # long format
    {cellsize}N{y}E{x}         # short format (NE order)
    {cellsize}E{x}N{y}         # short format (EN order)

The long format always uses meters while the short format aggregates cell sizes greater or equal to 1000m to km.

Usage

inspire_id_from_coords(
  coords,
  cellsize_m = NULL,
  short = FALSE,
  axis_order = "NE",
  llc = FALSE,
  tolerance = 1e-06,
  sample = 2000
)

inspire_id_to_coords(inspire, as_sf = FALSE, crs = NULL)

Arguments

coords

A list, matrix, or dataframe where the X and Y coordinates are either in the columns "x" and "y" or in the first and second column position, respectively. Column names are converted to lowercase.

Can also be a sf/sfc object in which case the coordinates are extracted using st_coordinates.

cellsize_m

A single integer representing the grid cell size in metres (e.g., 1000 for a 1 km grid). Required for spatial inputs.

short

If TRUE, generates short INSPIRE ID. Defaults to FALSE.

axis_order

A character string specifying the coordinate order for the output. This parameter is only used when short = TRUE. It can be one of:

  • "NE" (the default) to produce the format {cellsize}N{y}E{x}.

  • "EN" to produce the format {cellsize}E{x}N{y}.

llc

Do the coordinates in coords represent the lower-left corners of their cells? If FALSE, subtracts each coordinate by half of cellsize_m. If TRUE, leaves them as-is. Defaults to FALSE, i.e., treat coordinates as cell centroids.

tolerance

If res is NULL, controls the maximum acceptable difference between calculated cell spacings to consider them uniform. Defaults to 1e-6.

sample

If res is NULL, specifies the number of points to guess a resolution from. Defaults to 2000 to keep performance high. Increase this value if you are uncertain about the quality of your data.

inspire

A vector of INSPIRE IDs. Can be either legacy or non-legacy.

as_sf

Whether to return an object of class sfc or a dataframe.

crs

An optional numeric EPSG code or sf::st_crs object. If provided, this CRS will be assigned to all parsed coordinates, overriding any CRS information found in long-form IDs. If NULL (the default), the CRS is inferred from long-form IDs. When only short-form IDs are present, the function will default to EPSG:3035 (with a warning) for both sf and data.frame outputs.

Value

inspire_id_from_coords returns a character vector containing the INSPIRE identifiers.

inspire_id_to_coords returns a dataframe or sf dataframe (if as_sf = TRUE) containing the points extracted from the INSPIRE identifiers and information about the CRS and cell sizes. Note that the returned coordinates are always the centers of the grid cells as opposed to the lower-left corners.

Examples

# Generate IDs from a dataframe
coords <- data.frame(x = c(4334100, 4334200), y = 2684000)
gen <- inspire_id_from_coords(coords, llc = TRUE, cellsize_m = 100)
ext <- inspire_id_to_coords(gen)[c("x", "y")]
# Note: inspire_id_to_coords gives cell centers, so this won't be identical if llc=TRUE

# Generate long format IDs
inspire_id_from_coords(coords, llc = TRUE, cellsize_m = 100)
#> [1] "CRS3035RES100mN2684000E4334100" "CRS3035RES100mN2684000E4334200"

# Generate short format IDs with default "NE" axis order
inspire_id_from_coords(coords, llc = TRUE, cellsize_m = 1000, short = TRUE)
#> [1] "1kmN2684E4334" "1kmN2684E4334"

# Generate short format IDs with "EN" axis order
inspire_id_from_coords(coords, llc = TRUE, cellsize_m = 1000, short = TRUE, axis_order = "EN")
#> [1] "1kmE4334N2684" "1kmE4334N2684"

# Extract coordinates from short ID strings
inspire_id_to_coords("100mN34000E44000", crs = 3035)
#>    crs cellsize       y       x
#> 1 3035      100 3400000 4400000

# Generate IDs from an sf dataframe
if (requireNamespace("sf", quietly = TRUE)) {
  coords_df <- data.frame(x = c(4334100, 4334200), y = 2684000)
  coords_sf <- sf::st_as_sf(coords_df, coords = c("x", "y"), crs = 3035)
  inspire_id_from_coords(coords_sf, cellsize_m = 1000)
}
#> [1] "CRS3035RES1000mN2683500E4333600" "CRS3035RES1000mN2683500E4333700"