subset.RdSelect a subset of layers from a SpatRaster or select a subset of records (row) and/or variables (columns) from a SpatVector.
# S4 method for SpatRaster
subset(x, subset, negate=FALSE, NSE=FALSE, filename="", overwrite=FALSE, ...)
# S4 method for SpatVector
subset(x, subset, select, drop=FALSE, NSE=FALSE)SpatRaster or SpatVector
if x is a SpatRaster: integer or character to select layers
if x is a SpatVector: logical expression indicating the rows to keep (missing values are taken as FALSE)
expression, indicating columns to select
logical. If TRUE all layers that are not in the subset are selected
logical. If TRUE, non-standard evaluation (the use of unquoted variable names) is allowed. Set this to FALSE when calling subset from a function
logical. If TRUE, the geometries will be dropped, and a data.frame is returned
character. Output filename
logical. If TRUE, filename is overwritten
additional arguments for writing files as in writeRaster
if x is a SpatRaster: SpatRaster
if x is a SpatVector: SpatVector or, if drop=TRUE, a data.frame.
### SpatRaster
s <- rast(system.file("ex/logo.tif", package="terra"))
subset(s, 2:3)
#> class : SpatRaster
#> dimensions : 77, 101, 2 (nrow, ncol, nlyr)
#> resolution : 1, 1 (x, y)
#> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
#> coord. ref. : Cartesian (Meter)
#> source : logo.tif
#> names : green, blue
#> min values : 0, 0
#> max values : 255, 255
subset(s, c(3,2,3,1))
#> class : SpatRaster
#> dimensions : 77, 101, 4 (nrow, ncol, nlyr)
#> resolution : 1, 1 (x, y)
#> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
#> coord. ref. : Cartesian (Meter)
#> source : logo.tif
#> names : blue, green, blue, red
#> min values : 0, 0, 0, 0
#> max values : 255, 255, 255, 255
#equivalent to
s[[ c(3,2,3,1) ]]
#> class : SpatRaster
#> dimensions : 77, 101, 4 (nrow, ncol, nlyr)
#> resolution : 1, 1 (x, y)
#> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
#> coord. ref. : Cartesian (Meter)
#> source : logo.tif
#> names : blue, green, blue, red
#> min values : 0, 0, 0, 0
#> max values : 255, 255, 255, 255
s[[c("red", "green")]]
#> class : SpatRaster
#> dimensions : 77, 101, 2 (nrow, ncol, nlyr)
#> resolution : 1, 1 (x, y)
#> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
#> coord. ref. : Cartesian (Meter)
#> source : logo.tif
#> names : red, green
#> min values : 0, 0
#> max values : 255, 255
s$red
#> class : SpatRaster
#> dimensions : 77, 101, 1 (nrow, ncol, nlyr)
#> resolution : 1, 1 (x, y)
#> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
#> coord. ref. : Cartesian (Meter)
#> source : logo.tif
#> name : red
#> min value : 0
#> max value : 255
# expression based (partial) matching of names with single brackets
s["re"]
#> class : SpatRaster
#> dimensions : 77, 101, 2 (nrow, ncol, nlyr)
#> resolution : 1, 1 (x, y)
#> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
#> coord. ref. : Cartesian (Meter)
#> source : logo.tif
#> names : red, green
#> min values : 0, 0
#> max values : 255, 255
s["^re"]
#> class : SpatRaster
#> dimensions : 77, 101, 1 (nrow, ncol, nlyr)
#> resolution : 1, 1 (x, y)
#> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
#> coord. ref. : Cartesian (Meter)
#> source : logo.tif
#> name : red
#> min value : 0
#> max value : 255
# not with double brackets
# s[["re"]]
### SpatVector
v <- vect(system.file("ex/lux.shp", package="terra"))
subset(v, v$NAME_1 == "Diekirch", c("NAME_1", "NAME_2"))
#> class : SpatVector
#> geometry : polygons
#> dimensions : 5, 2 (geometries, attributes)
#> extent : 5.74414, 6.315773, 49.69933, 50.18162 (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326)
#> names : NAME_1 NAME_2
#> type : <chr> <chr>
#> values : Diekirch Clervaux
#> Diekirch Diekirch
#> Diekirch Redange
subset(v, NAME_1 == "Diekirch", c(NAME_1, NAME_2), NSE=TRUE)
#> class : SpatVector
#> geometry : polygons
#> dimensions : 5, 2 (geometries, attributes)
#> extent : 5.74414, 6.315773, 49.69933, 50.18162 (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326)
#> names : NAME_1 NAME_2
#> type : <chr> <chr>
#> values : Diekirch Clervaux
#> Diekirch Diekirch
#> Diekirch Redange
# or like this
v[2:3,]
#> class : SpatVector
#> geometry : polygons
#> dimensions : 2, 6 (geometries, attributes)
#> extent : 5.746118, 6.315773, 49.69933, 49.98745 (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326)
#> names : ID_1 NAME_1 ID_2 NAME_2 AREA POP
#> type : <num> <chr> <num> <chr> <num> <int>
#> values : 1 Diekirch 2 Diekirch 218 32543
#> 1 Diekirch 3 Redange 259 18664
v[1:2, 2:3]
#> class : SpatVector
#> geometry : polygons
#> dimensions : 2, 2 (geometries, attributes)
#> extent : 5.826232, 6.315773, 49.78479, 50.18162 (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326)
#> names : NAME_1 ID_2
#> type : <chr> <num>
#> values : Diekirch 1
#> Diekirch 2
v[1:2, c("NAME_1", "NAME_2")]
#> class : SpatVector
#> geometry : polygons
#> dimensions : 2, 2 (geometries, attributes)
#> extent : 5.826232, 6.315773, 49.78479, 50.18162 (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326)
#> names : NAME_1 NAME_2
#> type : <chr> <chr>
#> values : Diekirch Clervaux
#> Diekirch Diekirch