Internal function to create JPEG images from a multiband raster file. This function is used by s2_thumbnails, and it will be exported when it would be more generalised.
stack2rgb(
in_rast,
out_file = NULL,
bands = 1:3,
minval = 0,
maxval = 10000,
format = "JPEG",
compress = "90",
bigtiff = FALSE,
proc_mode = "raster",
tmpdir = NA
)
The path of the output image; alternatively, the output image
as RasterBrick (if out_rast = NULL
).
Input raster (as Raster*
or stars
object).
(optional) Path of the output RGB JPEG image; if NULL (default), a RasterBrick will be returned.
(optional) 3-length integer argument, with the position of the three bands to be used respectively for red, green and blue.
(optional) the value corresponding to black (default: 0). Also a 3-length vector is accepted (min values for red, green and blue respectively).
(optional) the value corresponding to white (default: 10000). Also a 3-length vector is accepted (max values for red, green and blue respectively).
(optional) Format of the output file (in a format recognised by GDAL). Default is JPEG.
(optional) In the case a GTiff format is present, the compression indicated with this parameter is used. In the case a JPEG format is present, the compression indicates the quality (integer, 0-100). In the case a GTiff format is present and an integer 0-100 number is provided, this is interpreted as the quality level of a JPEG compression.
(optional) Logical: if TRUE, the creation of a BigTIFF is forced (default is FALSE). This option is used only in the case a GTiff format was chosen.
(optional) Character: if "gdal_calc"
,
gdal_calc
routines are used to compute indices;
if "raster"
(default) or "stars"
, R functions are instead used
(using respectively raster
or stars
routines).
Note: default value ("raster"
) is the only fully supported mode.
"gdal_calc"
can be used only if a runtime GDAL environment can be properly
configured (no assistance is provided in case of GDAL-related problems).
"raster"
mode is experimental.
See s2_calcindices()
for further details.
(optional) Path where intermediate files will be created.
Default is a temporary directory.
If tmpdir
is a non-empty folder, a random subdirectory will be used.
Luigi Ranghetti, phD (2019)
L. Ranghetti, M. Boschetti, F. Nutini, L. Busetto (2020). "sen2r": An R toolbox for automatically downloading and preprocessing Sentinel-2 satellite data. Computers & Geosciences, 139, 104473. tools:::Rd_expr_doi("10.1016/j.cageo.2020.104473"), URL: https://sen2r.ranghetti.info/.