def calulate_indices(filepath, asset_dict, indices):
''' Create image files for indices
:param filepath (str): Full path to directory containing satellite scenes in default structure created
by sat-search load --download
:param asset_dict (dict): Keys = asset (band) names in scene files (e.g. 'B01', 'B02'); Values = value names
corresponding to keys (e.g. 'red', 'nir')
:param indices (list): Which indices to generate? Options include any index included in gippy.alg.indices
:return: None (writes files to disk)
'''
subdirs = [x[0] for x in walk(filepath)]
subdirs = subdirs[1:len(subdirs)]
for folder in subdirs:
# Filepath points to folder of geotiffs of Sentinel 2 time-series of bands 4 (red) and 8 (nir)
files = [folder + '/' + f for f in listdir(folder) if not f.startswith('.')]
# Asset (band) names
pattern = '[^_.]+(?=\.[^_.]*$)'
bands = [re.search(pattern, f).group(0) for f in files]
# Match band names
bands = [asset_dict.get(band, band) for band in bands]
img = GeoImage.open(filenames=files, bandnames=bands, nodata=0)
for ind in indices:
alg.indices(img, products=[ind], filename=folder + '/index_' + ind + '.tif')
img = None
def open_image(item, keys=None, nodata=0, download=False):
""" Open these asset keys from scene as a gippy GeoImage """
if keys is None:
keys = item.assets.keys()
logger.debug('Opening item %s (%s)' % (item.id, ','.join(keys)))
if download:
# download items first
fnames = item.download(keys)
geoimg = GeoImage.open(fnames)
else:
# use GDAL vsi curl driver
filenames = [
item.asset(k)['href'].replace('https:/', '/vsicurl/https:/')
for k in keys
]
geoimg = GeoImage.open(filenames, update=False)
geoimg.set_bandnames(keys)
geoimg.set_nodata(nodata)
return geoimg