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Create a square grid

Source: R/fonctions_grilles.R
create_grid_niv.Rd

Create a square grid

Usage

create_grid_niv(
  tab,
  taille,
  nom_id_car = "id_carreau",
  point_base = c(0, 0),
  eurostat = FALSE
)

Arguments

tab

A data.table with at least a column for x coordinate, a column for y coordinate and a column specifying the coordinate reference system (crs). For exemple, crs = 3035 for the LAEA projection in Europe.

taille

The size of the mesh in meters.

nom_id_car

A character, the name of the variable for the identifier of the mesh. By default it is "id_carreau".

point_base

vector of 2 numeric values, coordinates of the reference point of the grid. If eurostat = TRUE, the value used will be automatically c(0,0).

eurostat

boolean, whether the id created has to comply the eurostat inspire requirements or not, especially for the conversion in km while using a resolution >= 1000m.

Value

The data.table tab with one more column beeing the identifier of the mesh of the square grid. The name of the mesh is based on the Inspire norm : "if the coordinate reference system is projected, the word RES followed by the grid resolution in meters and the letter m. Then, the letter N followed by the northing value in meters, and the letter E followed by the easting value in meters too" (Inspire, Data Specification for the spatial data theme Statistical Units, 10/12/2013, page 30). The given position is the position of the lower left cell corner.

Examples

library(data.table)
tab <- as.data.table(
  data.frame(
    id_obs = 1:10,
    x = rnorm(10,3e6,1e4),
    y = rnorm(10, 2e6, 1e4),
    crs = 3035)
)
res <- create_grid_niv(tab, 200)