Last data update: 2014.03.03
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R: Convert RGB three band to single band colour table
Convert RGB three band to single band colour table
Description
This function converts a three-band GDALReadOnlyDataset into a single band of colour indices as a GDALTransientDataset.
Usage
RGB2PCT(x, band, driver.name = 'MEM', ncolors = 256, set.ctab = TRUE)
Arguments
x |
a three-band GDALReadOnlyDataset object
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band |
a vector of numbers, recycled up to 3 in length
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driver.name |
default MEM
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ncolors |
a number of colours between 2 and 256
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set.ctab |
default TRUE, when the dithered dataset handle is returned, otherwise a list of the dataset and the PCT colour table
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Value
The value returned is a either GDALTransientDataset or a list of a GDALTransientDataset and a colour table.
Author(s)
Tim Keitt
References
http://www.gdal.org/
Examples
logo <- system.file("pictures/Rlogo.jpg", package="rgdal")[1]
x <- GDAL.open(logo)
dim(x)
dx <- RGB2PCT(x, band=1:3)
displayDataset(dx)
dim(dx)
GDAL.close(x)
GDAL.close(dx)
Results
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