Conversion to a SpatVector of lines

Conversion of a SpatRaster, SpatVector or SpatExtent to a SpatVector of lines.

Usage

# S4 method for class 'SpatRaster'
as.lines(x)

# S4 method for class 'SpatVector'
as.lines(x)

# S4 method for class 'SpatExtent'
as.lines(x, crs="")

# S4 method for class 'matrix'
as.lines(x, crs="")

Arguments

x

SpatRaster, SpatVector, SpatExtent or matrix. If x is a matrix it should have two columns for a single line, or four columns, where each row has the start and end coordinates (x, y) for lines

crs

character. The coordinate reference system (see crs)

Value

SpatVector

See also

as.points, as.polygons

Examples

r <- rast(ncols=2, nrows=2)
values(r) <- 1:ncell(r)

as.lines(r)
#>  class       : SpatVector 
#>  geometry    : lines 
#>  dimensions  : 6, 0  (geometries, attributes)
#>  extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#>  coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84) 

as.lines(ext(r), crs=crs(r))
#>  class       : SpatVector 
#>  geometry    : lines 
#>  dimensions  : 1, 0  (geometries, attributes)
#>  extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#>  coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84) 

if  (gdal() >= "3.0.0") {
  p <- as.polygons(r)
  as.lines(p)
}
#>  class       : SpatVector 
#>  geometry    : lines 
#>  dimensions  : 4, 1  (geometries, attributes)
#>  extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#>  coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84) 
#>  names       : lyr.1
#>  type        : <int>
#>  values      :     1
#>                    2
#>                    3


## with a matrix
s <- cbind(1:5, 1:5)
e <- cbind(1:5, 0)

as.lines(s)
#>  class       : SpatVector 
#>  geometry    : lines 
#>  dimensions  : 1, 0  (geometries, attributes)
#>  extent      : 1, 5, 1, 5  (xmin, xmax, ymin, ymax)
#>  coord. ref. :  
as.lines(cbind(s, e), "+proj=longlat")
#>  class       : SpatVector 
#>  geometry    : lines 
#>  dimensions  : 5, 0  (geometries, attributes)
#>  extent      : 1, 5, 0, 5  (xmin, xmax, ymin, ymax)
#>  coord. ref. : +proj=longlat +datum=WGS84 +no_defs