| create_image_collection {gdalcubes} | R Documentation |
This function iterates over files or GDAL dataset identifiers and extracts datetime, image identifiers, and band information according to a given collection format.
create_image_collection( files, format = NULL, out_file = tempfile(fileext = ".sqlite"), date_time = NULL, band_names = NULL, use_subdatasets = FALSE, unroll_archives = TRUE, quiet = FALSE )
files |
character vector with paths to image files on disk or any GDAL dataset identifiers (including virtual file systems and higher level drivers or GDAL subdatasets) |
format |
collection format, can be either a name to use predefined formats (as output from |
out_file |
optional name of the output SQLite database file, defaults to a temporary file |
date_time |
vector with date/ time for files; can be of class character, Date, or POSIXct (argument is only applicable for image collections without collection format) |
band_names |
character vector with band names, length must match the number of bands in provided files (argument is only applicable for image collections without collection format) |
use_subdatasets |
logical; use GDAL subdatasets of provided files (argument is only applicable for image collections without collection format) |
unroll_archives |
automatically convert .zip, .tar archives and .gz compressed files to GDAL virtual file system dataset identifiers (e.g. by prepending /vsizip/) and add contained files to the list of considered files |
quiet |
logical; if TRUE, do not print resulting image collection if return value is not assigned to a variable |
An image collection is a simple SQLite database file that indexes and references existing image files / GDAL dataset identifiers.
Collections can be created in two different ways: First, if a collection format is specified (argument format), date/time, bands, and metadata are automatically
extracted from provided files / GDAL datasets. Second, image collections can be created without collection format by manually specifying date/time of images
(argument date_time) and (optional) names of bands. In this case, however, all provided images must contain the same bands. If this is not
possible for a dataset, a collection format must be used.
image collection proxy object, which can be used to create a data cube using raster_cube
# create image collection from example Landsat data only
# if not already done in other examples
if (!file.exists(file.path(tempdir(), "L8.db"))) {
L8_files <- list.files(system.file("L8NY18", package = "gdalcubes"),
".TIF", recursive = TRUE, full.names = TRUE)
create_image_collection(L8_files, "L8_L1TP", file.path(tempdir(), "L8.db"))
}