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Crop a raster using GDAL

Source: R/terra_gdal_crop.R
terra_gdal_crop.Rd

This function is a wrapper for gdalUtilities::gdal_translate() for use with terra objects.

Usage

terra_gdal_crop(
  x,
  ext,
  n_threads = 1,
  filename = tempfile(fileext = ".tif"),
  datatype = "FLT4S",
  cache_limit = 200,
  tiled = FALSE,
  bigtiff = FALSE,
  compress = "LZW",
  verbose = TRUE,
  NAflag = NULL,
  output_raster = TRUE
)

Arguments

x

terra::rast() Raster object with source data.

ext

terra::ext() Raster extent object.

n_threads

integer Number of computational threads to use for data processing. To reduce run time, it is strongly recommended to set this parameter based on available resources (see Examples section below). Defaults to 1.

filename

character Filename for output raster. Defaults to tempfile(fileext = ".tif").

datatype

character Value indicating the data type for saving data. Defaults to "FLT4S".

cache_limit

integer Number of MB to use for GDAL caching. Defaults to 200.

tiled

logical Value indicating if GeoTIFF files should be tiled. Defaults to FALSE.

bigtiff

logical Value indicating the data should be stored in BIGTIFF format. Defaults to FALSE.

compress

character Value indicating compression format. Available options include "LZW" and "DEFLATE". Defaults to "LZW".

verbose

logical Should information be displayed during processing? Defaults to TRUE.

NAflag

numeric Value for representing missing (NA) values. A "none" value can also be used to indicate that no flag should be set. Defaults to NULL such that the value is determined automatically.

output_raster

logical Should a raster (terra::rast()) object be returned? If FALSE then the file path for the resulting file is returned. Defaults to TRUE.

Value

A terra::rast() raster object.

Examples

# please ensure that the gdalUtilities package is installed
# to run this example

# create raster with data
x <- rast(
  ncols = 40, nrows = 40, xmin = -110, xmax = -90, ymin = 40, ymax=60,
  crs = "+proj=longlat +datum=WGS84"
)
values(x) <- seq_len(ncell(x))

# create extent for cropping
y <- ext(x) - c(5, 2.5, 1, 1.5)

# crop data
z <- terra_gdal_crop(x, y)

# preview result
print(z)
#> class       : SpatRaster 
#> size        : 35, 25, 1  (nrow, ncol, nlyr)
#> resolution  : 0.5, 0.5  (x, y)
#> extent      : -105, -92.5, 41, 58.5  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326) 
#> source      : file9fcb2b777622.tif 
#> name        : lyr.1