This function converts a three-band GDALReadOnlyDataset into a single band of colour indices as a GDALTransientDataset.

RGB2PCT(x, band, driver.name = 'MEM', ncolors = 256, set.ctab = TRUE)

Arguments

x

a three-band GDALReadOnlyDataset object

band

a vector of numbers, recycled up to 3 in length

driver.name

default MEM

ncolors

a number of colours between 2 and 256

set.ctab

default TRUE, when the dithered dataset handle is returned, otherwise a list of the dataset and the PCT colour table

Value

The value returned is a either GDALTransientDataset or a list of a GDALTransientDataset and a colour table.

References

https://gdal.org/

Author

Tim Keitt

Examples

if (FALSE) { logo <- system.file("pictures/Rlogo.jpg", package="rgdal")[1] x <- GDAL.open(logo) dim(x) dx <- RGB2PCT(x, band=1:3) displayDataset(dx, reset.par=FALSE) dim(dx) GDAL.close(x) GDAL.close(dx) }