datatype: Data type of a SpatRaster or SpatVector

Description

Get the data types of the fields (attributes, variables) of a SpatVector or of the file(s) associated with a SpatRaster. A (layer of a) SpatRaster has no datatype if it has no values, or if the values are in memory.

Usage

# S4 method for SpatRaster
datatype(x, bylyr=TRUE)
# S4 method for SpatVector
datatype(x)

Value

character

Arguments

x: SpatRaster or SpatVector
bylyr: logical. If TRUE a value is returned for each layer. Otherwise, a value is returned for each data source (such as a file)

Details

Setting the data type is useful if you want to write values to disk with writeRaster. In other cases you can use functions such as round and floor, or as.bool

raster datatypes are described by 5 characters. The first three indicate whether the values are integer or decimal values. The fourth character indicates the number of bytes used to save the values on disk, and the last character indicates whether the numbers are signed (that is, can be negative and positive values) or not (only zero and positive values allowed)

The following raster datatypes are available:

Datatype definition	minimum possible value	maximum possible value
`INT1U`	0	255
`INT2U`	0	65,534
`INT4U`	0	4,294,967,296
`INT8U`	0	18,446,744,073,709,551,616
`INT2S`	-32,767	32,767
`INT4S`	-2,147,483,647	2,147,483,647
`INT8S`	-9,223,372,036,854,775,808	9,223,372,036,854,775,808
`FLT4S`	-3.4e+38	3.4e+38
`FLT8S`	-1.7e+308	1.7e+308

For all integer types, except the single byte types, the lowest (signed) or highest (unsigned) value is used to store NA.

Note that very large integer numbers may be imprecise as they are internally represented as decimal numbers.

INT4U is available but they are best avoided as R does not support 32-bit unsigned integers.

Examples

Run this code

f <- system.file("ex/lux.shp", package="terra")
v <- vect(f)
datatype(v)

f <- system.file("ex/elev.tif", package="terra")
r <- rast(f)
datatype(r)

# no data type
datatype(rast())