subset: Subset a SpatRaster or a SpatVector

In terra: Spatial Data Analysis

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 signature 'SpatRaster'
subset(x, subset, negate=FALSE, NSE=FALSE, filename="", overwrite=FALSE, ...)

## S4 method for signature 'SpatVector'
subset(x, subset, select, drop=FALSE, NSE=FALSE)

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

Value

if x is a SpatRaster: SpatRaster

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

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")]

terra documentation built on Jan. 17, 2023, 5:18 p.m.