GDAL Open ZIP returns None

Question

I'm trying to open Sentinel-2 bands directly from the .zip L2A files with GDAL, but this only returns a None. Unzipping the folder prior to reading the file yield better results, but still randomly returns some None from time to time. I'm using gdal 2.2.2.

import numpy as np 
import osgeo.gdal as gdal
import zipfile, os

from libs.generic import filemanager as fm
os.environ['CPL_ZIP_ENCODING'] = 'UTF-8'

class s2img:

def __init__(self):
    return None

def readL2A(self, zippath):

    try:
        zipf = zipfile.ZipFile(zippath, 'r')
    except:
        raise IOError("Unable to open ZIP-file.")

    flist = zipf.namelist()
    zipf.close()

    bandnames = []
    bandnames.append( ['B02','B03','B04','B08'] )
    bandnames.append( ['B05','B06','B07','B8A','B11','B12','SCL'] )
    bandnames.append( ['B01','B09'] )

    bandres = ['10m','20m','60m']

    fnames = [f for f in flist if 'IMG_DATA' in f]
    fnames = [f for f in fnames if f.endswith('.jp2')]
    for r in range(len(bandnames)-1):
        res = bandres[r]
        resbnames = bandnames[r]
        fresnames = [f for f in fnames if res in f]

        for b in range(len(resbnames)):
            fname= [f for f in fresnames if resbnames[b] in f ][0]
            chn_fn = "/vsizip/%s/%s" % (zippath,fname)
            gobj = gdal.Open(chn_fn, gdal.GA_ReadOnly )

            # DO STUFF 
    return None

Answer 1

Found the problem. In order for gdal to be able to properly read the "sentinel-2.jp2" bands it needs supporting files. The location of the these can be specified by properly setting the "GDAL_DATA" environment variable: (https://trac.osgeo.org/gdal/wiki/FAQInstallationAndBuilding#HowtosetGDAL_DATAvariable)

If you're using Ananconda as the python library manager, then at the beginning of your script you should insert a line like this:

os.environ['GDAL_DATA'] = "C:/Users/B/Anaconda3/Library/share/gdal"

If you're using a virtual environment then the path should look something like this:

os.environ['GDAL_DATA'] = "C:/Users/B/Anaconda3/envs/geopy/Library/share/gdal/",

where "geopy" is the name of my environment.

However, this doesn't explain why on my other pc I didn't need to add this line to the code in order for the script to run properly on already unzipped images.