How to enable LZW compression in a QGIS python code?

Question

I have this simple code that batch sieves all the raster in a given directory. I found outthat the resulting output files (241MB )are pretty much larger than the input(~31MB). In ArcGIS, there is a way to enable compression like LZW, how to do it it QGIS python? Is there a way to insert it in this code?

from qgis.core import * #importing the QGIS processing core
import os, subprocess, glob

input = "/data/brent/GAUP/sen2agri_two_years/"
output_dir = "/data/brent/GAUP/sen2agri_two_years/sieved//"
os.chdir(input)

for fname in glob.glob("S2*.TIF"):
    print fname
    name= list(os.path.splitext(fname))
    name[0] = name[0] + "_sieved"
    newName = "".join(name)
    print "processing " + newName
    subprocess.call(["gdal_sieve.py", "-st", "20", "-4", fname, "-of", "GTiff", output_dir+newName])

Answer 1

I add a few lines in my code using gdal_translate:

from qgis.core import * #importing the QGIS processing core
from qgis.utils import iface #importing the iface
import os, subprocess, glob

input = "/data/brent/GAUP/sen2agri_two_years/"
output_dir = "/data/brent/GAUP/sen2agri_two_years/sieved//"
os.chdir(input)

#Main Process
for fname in glob.glob("S2*.TIF"):
    name= list(os.path.splitext(fname))
    name[0] = name[0] + "_sieved"
    newName = "".join(name)
    print "processing " + newName
    subprocess.call(["gdal_sieve.py", "-st", "20", "-8", fname, "-of", "GTiff",  output_dir+newName])
    os.chdir("/data/brent/GAUP/sen2agri_two_years/sieved/")
    output_dir2 = "/data/brent/GAUP/sen2agri_two_years/sieved//"
    newName2 = newName.replace("_sieved", "_com")
    subprocess.call(["gdal_translate", "-of", "GTiff", newName, output_dir2+newName2, "-co", "compress=LZW"])
    os.chdir(input)

print "Finished Sieving!"