set spatial coordinates to create a Spatial object, or retrieve spatial coordinates from a Spatial object

Usage

coordinates(obj, ...)
coordinates(object) <- value

Arguments

obj: object deriving from class "Spatial"
object: object of class "data.frame"
value: spatial coordinates; either a matrix, list, or data frame with numeric data, or column names, column number or a reference: a formula (in the form of e.g. ~x+y), column numbers (e.g. c(1,2)) or column names (e.g. c("x","y")) specifying which columns in object are the spatial coordinates. If the coordinates are part of object, giving the reference does not duplicate them, giving their value does duplicate them in the resulting structure.
...: additional arguments that may be used by particular methods

Value

usually an object of class SpatialPointsDataFrame; if the coordinates set cover the full set of variables in object, an object of class SpatialPoints is returned

Examples

# data.frame
data(meuse.grid)
coordinates(meuse.grid) <- ~x+y
gridded(meuse.grid) <- TRUE
class(meuse.grid)
#> [1] "SpatialPixelsDataFrame"
#> attr(,"package")
#> [1] "sp"
bbox(meuse.grid)
#>      min    max
#> x 178440 181560
#> y 329600 333760

data(meuse)
meuse.xy = meuse[c("x", "y")]
coordinates(meuse.xy) <- ~x+y
class(meuse.xy)
#> [1] "SpatialPoints"
#> attr(,"package")
#> [1] "sp"