gdalraster (version 1.11.1)

buildVRT: Build a GDAL virtual raster from a list of datasets

Description

buildVRT() is a wrapper of the gdalbuildvrt command-line utility for building a VRT (Virtual Dataset) that is a mosaic of the list of input GDAL datasets (see https://gdal.org/programs/gdalbuildvrt.html).

Usage

buildVRT(vrt_filename, input_rasters, cl_arg = NULL, quiet = FALSE)

Value

Logical indicating success (invisible TRUE). An error is raised if the operation fails.

Arguments

vrt_filename

Character string. Filename of the output VRT.

input_rasters

Character vector of input raster filenames.

cl_arg

Optional character vector of command-line arguments to gdalbuildvrt.

quiet

Logical scalar. If TRUE, a progress bar will not be displayed. Defaults to FALSE.

Details

Several command-line options are described in the GDAL documentation at the URL above. By default, the input files are considered as tiles of a larger mosaic and the VRT file has as many bands as one of the input files. Alternatively, the -separate argument can be used to put each input raster into a separate band in the VRT dataset.

Some amount of checks are done to assure that all files that will be put in the resulting VRT have similar characteristics: number of bands, projection, color interpretation.... If not, files that do not match the common characteristics will be skipped. (This is true in the default mode for virtual mosaicing, and not when using the -separate option).

In a virtual mosaic, if there is spatial overlap between input rasters then the order of files appearing in the list of sources matter: files that are listed at the end are the ones from which the data will be fetched. Note that nodata will be taken into account to potentially fetch data from less priority datasets.

See Also

rasterToVRT()

Examples

# build a virtual 3-band RGB raster from individual Landsat band files
b4_file <- system.file("extdata/sr_b4_20200829.tif", package="gdalraster")
b5_file <- system.file("extdata/sr_b5_20200829.tif", package="gdalraster")
b6_file <- system.file("extdata/sr_b6_20200829.tif", package="gdalraster")
band_files <- c(b6_file, b5_file, b4_file)
vrt_file <- file.path(tempdir(), "storml_b6_b5_b4.vrt")
buildVRT(vrt_file, band_files, cl_arg = "-separate")
ds <- new(GDALRaster, vrt_file)
ds$getRasterCount()
plot_raster(ds, nbands=3, main="Landsat 6-5-4 (vegetative analysis)")
ds$close()

vsi_unlink(vrt_file)