As a test you can skip the whole python debacle and try this:
gdal_translate -f COG -co COMPRESS=DEFLATE -scale 0 255 -ot Byte
source.tif target.tif
On 6/1/23 07:35, afernandez wrote:
Hello,
I'm generating a raster file with GDAL. The pseudo-code (where the
raster is loaded as 'var') for the colored version reads:
# Initial manipulations
dims = var.dimensions
shape = var.shape
driver_name = 'GTIFF'
driver = gdal.GetDriverByName(driver_name)
np_dtype = var.dtype
type_code = gdal_array.NumericTypeCodeToGDALTypeCode(np_dtype)
gdal_ds = driver.Create(_my_path_, cols, rows, 1,
gdal.GDT_UInt16)
gdal_ds.SetProjection(_my_projection_)
gdal_ds.SetGeoTransform(_my_transformation_)
# Creation of the bands and scaled matrix
band = gdal_ds.GetRasterBand(1)
data = var[_chosen_index_]
data = ma.getdata(data)
data_scaled = np.interp(data, (data.min(), data.max()), (0,
255))
data_scaled2 = data_scaled.astype(int) # This is to rescale
into integers so that it can color the layer
# *** Lines to set up the color palette ***
# Write the array to band once everything has been rescaled
band.WriteArray(data_scaled2)
gdal_ds.FlushCache()
This works well but the problem is that the generated file becomes too
large and difficult to work with. If I change to a black and white
representation by simply changing the 7th line to:
gdal_ds = driver.Create(out_path, cols, rows, 1, type_code)
The new file has a size smaller than 1% of the colored one. I was
wondering if there is anything intermediate (with colors but generating
a smaller size) or if I would need a more radical approach such as using
a driver different from GTIFF or something else.
Thanks.
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