Stefan,
in processing Collection-1 Landsat 8 products, `i.landsat8.qc` deserves
an update [0][1]. Please note that Pre-Collection products are removed
from EarthExplorer [2][3].
See:
[0] https://landsat.usgs.gov/sites/default/files/documents/landsat_QA_tools_userguide.pdf
[1] https://landsat.usgs.gov/collectionqualityband
[2] https://landsat.usgs.gov/september-1-2017-countdown-landsat-pre-collection-datasets-removal
[3] https://landsat.usgs.gov/oct-3-2017-pre-collection-dataset-removal-prompts-ee-changes
Below, bits and descriptions transferred in python dictionaries,
blindly following the script's current structure (kept "old" and "new"
for comparison). I would like your view on this, or anyone else's who is
interested.
What do you think of:
- introducing a `collection=` option in the module and make it treat
both, Pre-Collection and Collection-1 products?
- removing Pre-collection QA bits altogether?
Nikos
--
Hier Pre-Collection und Collection-1 zusammen:
"""
Pre-Collection populated bits:
0 Designated Fill
1 Dropped Frame
2 Terrain Occlusion
3 Reserved (not currently used)
4-5 Water Confidence
6-7 Reserved for cloud shaddow
8-9 Vegetation confidence
10-11 Snow/Ice confidence
12-13 Cirrus confidence
14-15 Cloud confidence
"""
# Define bit length (single or double bits) -- Pre-Collection
bl = {'designated_fill': 1,
'dropped_frame': 1,
'terrain_occlusion': 1,
# 'reserved': 1,
'water': 2,
'cloud_shadow': 2,
'vegetation': 2,
'snow_ice': 2,
'cirrus': 2,
'cloud': 2}
# Define bit position start -- Pre-Collection
bps = {
'designated_fill': 0,
'dropped_frame': 1,
'terrain_occlusion': 2,
# 'reserved': 3,
'water': 4,
'cloud_shadow': 6,
'vegetation': 8,
'snow_ice': 10,
'cirrus': 12,
'cloud': 14}
"""
Collection-1 populated bits
0 Designated Fill
1 Terrain Occlusion
2-3 Radiometric Saturation
4 Cloud
5-6 Cloud Confidence
7-8 Cloud Shadow Confidence
9-10 Snow/Ice confidence
11-12 Cirrus confidence
13
14
15
"""
# Define bit length (single or double bits) -- Collection-1
bit_length = {'designated_fill': 1,
'terrain_occlusion': 1,
'radiometric_saturation': 2,
'cloud': 1,
'cloud_confidence': 2,
'cloud_shadow_confidence': 2,
'snow_ice_confidence': 2,
'cirrus_confidence': 2,
# 'reserved': 1,
# 'reserved': 1}
# Define bit position start -- Collection-1
bit_position_start = {
'designated_fill': 0,
'terrain_occlusion': 1,
'radiometric_saturation': 2,
'cloud': 4,
'cloud_confidence': 5,
'cloud_shadow_confidence': 7,
'snow_ice_confidence': 9,
'cirrus_confidence': 11,
# 'reserved': 13,
# 'reserved': 14,
# 'reserved': 15}
"""
Pre-Collection
For the single bits (0, 1, 2, and 3):
0 = No, this condition does not exist
1 = Yes, this condition exists.
"""
"""
Collection-1
For the single bits (0, 1, and 4):
0 = "No" = This condition does not exist
1 = "Yes" = This condition exists
"""
# Define single bits dictionary -- Identical for Pre- and C1
single_bits = {'No': '0',
'Yes': '1'}
"""
Collection-1
For radiometric saturation bits (2-3), read from left to right, represent how many bands contain saturation:
00 - No bands contain saturation
01 - 1-2 bands contain saturation
10 - 3-4 bands contain saturation
11 - 5 or more bands contain saturation
"""
radiometric_saturation = {'No bands contain saturation': '00',
'1-2 bands contain saturation': '01',
'3-4 bands contain saturation': '10',
'5 or more bands contain saturation': '11'}
"""
Pre-Collection
The double bits (4-5, 6-7, 8-9, 10-11, 12-13, and 14-15), read from left to
right, represent levels of confidence that a condition exists:
00 = 'Not Determined' = Algorithm did not determine the status
of this condition
01 = 'No' = Algorithm has low to no confidence that this condition exists
(0-33 percent confidence)
10 = 'Maybe' = Algorithm has medium confidence that this condition exists
(34-66 percent confidence)
11 = 'Yes' = Algorithm has high confidence that this condition exists
(67-100 percent confidence).
"""
# Define double bits dictionary -- Pre-Collection
double_bits = {'Not Determined': '00',
'No': '01',
'Maybe': '10',
'Yes': '11'}
"""
Collection-1
For the remaining double bits (5-6, 7-8, 9-10, 11-12), read from left to
right, represent levels of confidence that a condition exists:
00 = "Not Determined" = Algorithm did not determine the status of this
condition / "No" = This condition does not exist
01 = "Low" = Algorithm has low to no confidence that this condition exists
(0-33 percent confidence)
10 = "Medium" = Algorithm has medium confidence that this condition exists
(34-66 percent confidence)
11 = "High" = Algorithm has high confidence that this condition exists
(67-100 percent confidence
"""
# Define double bits dictionary -- Colletion-1
double_bits_c1 = {'Not Determined': '00',
'Low': '01',
'Medium': '10',
'High': '11'}