R: Check for longitude/latitude crs

is.lonlat {terra} | R Documentation

## Check for longitude/latitude crs

### Description

Test whether a SpatRaster or SpatVector has a longitude/latitude coordinate reference system (CRS), or perhaps has one. That is wen the CRS is unknown (`""`) but the x coordinates are within -181 and 181 and the y coordinates are within -90.1 and 90.1. For a SpatRaster you can also test if it is longitude/latitude and "global" (covers all longitudes).

The form `isLonLat` is depracated. Use `is.lonlat`

### Usage

    ## S4 method for signature 'SpatRaster'
    is.lonlat(x, perhaps=FALSE, warn=TRUE, global=FALSE)

    ## S4 method for signature 'SpatVector'
    is.lonlat(x, perhaps=FALSE, warn=TRUE)

    ## S4 method for signature 'SpatRaster'
    isLonLat(x)

    ## S4 method for signature 'SpatVector'
    isLonLat(x)

### Arguments

`x` | SpatRaster or SpatVector
`perhaps` | logical. If `TRUE` and the crs is unknown, the method returns `TRUE` if the coordinates are plausible for longitude/latitude
`warn` | logical. If `TRUE`, a warning is given if the CRS is unknown or when the CRS is longitude/latitude but the coordinates do not match that
`global` | logical. If `TRUE`, the method tests if the raster covers all longitudes (from -180 to 180 degrees) such that the extreme columns are in fact adjacent

### Value

logical

### Examples

    r <- rast()
    is.lonlat(r)
    is.lonlat(r, global=TRUE)

    crs(r) <- ""
    is.lonlat(r)
    is.lonlat(r, perhaps=TRUE, warn=FALSE)

    crs(r) <- "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100 +ellps=WGS84"
    is.lonlat(r)

[Package terra version 1.4-7 Index]