terra (version 1.8-5)

subset: Subset a SpatRaster or a SpatVector

Description

Select a subset of layers from a SpatRaster or select a subset of records (row) and/or variables (columns) from a SpatVector.

Usage

# 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)

Value

if x is a SpatRaster: SpatRaster

if x is a SpatVector: SpatVector or, if drop=TRUE, a data.frame.

Arguments

x

SpatRaster or SpatVector

subset

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)

select

expression, indicating columns to select

negate

logical. If TRUE all layers that are not in the subset are selected

NSE

logical. If TRUE, non-standard evaluation (the use of unquoted variable names) is allowed. Set this to FALSE when calling subset from a function

drop

logical. If TRUE, the geometries will be dropped, and a data.frame is returned

filename

character. Output filename

overwrite

logical. If TRUE, filename is overwritten

...

additional arguments for writing files as in writeRaster

Examples

### SpatRaster
s <- rast(system.file("ex/logo.tif", package="terra"))   
subset(s, 2:3)
subset(s, c(3,2,3,1))

#equivalent to 
s[[ c(3,2,3,1) ]]

s[[c("red", "green")]]
s$red

# expression based (partial) matching of names with single brackets
s["re"]
s["^re"]

# 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"))

subset(v, NAME_1 == "Diekirch", c(NAME_1, NAME_2), NSE=TRUE)

# or like this
v[2:3,]
v[1:2, 2:3]
v[1:2, c("NAME_1", "NAME_2")]