burn_mapper / utils /NBR_calculations.py
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import ee
''' 0 Good quality fire
1 Good quality fire-free land
2 Invalid due to opaque cloud
3 Invalid due to surface type or sunglint or LZA threshold exceeded or off earth or missing input data
4 Invalid due to bad input data
5 Invalid due to algorithm failure'''
# Bit-masking
BitMask_0 = 1 << 0
BitMask_1 = 1 << 1
BitMask_2 = 1 << 2
BitMask_3 = 1 << 3
BitMask_4 = 1 << 4
BitMask_5 = 1 << 5
BitMask_6 = 1 << 6
BitMask_7 = 1 << 7
BitMask_8 = 1 << 8
BitMask_9 = 1 << 9
def GcalcNBR (goesImg, aoi):
#day = ee.Date(eachImg.get('system:time_start')).get('day','America/Los_Angeles')
fireMode = goesImg.select('fireMode')
fireMin = goesImg.select('fireMin')
CMI_QF3 = goesImg.select('DQF_C03').int()
CMI_QF6 = goesImg.select('DQF_C06').int()
# To include active fire pixels - fireMin.lt(2)\ for next line
QF_Mask = (fireMin.eq(1)\
.Or(fireMin.gt(3)))\
.And(CMI_QF3.lt(2))\
.And(CMI_QF6.lt(2))\
.rename('QFmask');
GOESm = goesImg.select(['CMI_C03','CMI_C06']).updateMask(QF_Mask)
NBR = GOESm.normalizedDifference(['CMI_C03', 'CMI_C06']).toFloat().rename('NBR')
return goesImg.addBands([NBR,QF_Mask])
def GcalcCCsingle (goesImg):
fireDQF = goesImg.select('DQF').int()
CMI_QF3 = goesImg.select('DQF_C03').int()
CMI_QF6 = goesImg.select('DQF_C06').int()
#Right now, cloud mask is excluding clouds and water; active fire, bad data and fire free are unmasked. NBR mask exlcudes fire
F_Mask = fireDQF.eq(0)
C_Mask = (fireDQF.lt(2).Or(fireDQF.gt(2))).rename('C_Mask')
#.And(CMI_QF3.lt(2)).And(CMI_QF6.lt(2)).rename('C_Mask')
QF_Mask = (fireDQF.eq(1).Or(fireDQF.gt(3)))\
.And(CMI_QF3.lt(2)).And(CMI_QF6.lt(2)).rename('QFmask')
GOESmasked = goesImg.select(['CMI_C03','CMI_C06']).updateMask(QF_Mask)
NBRmasked = GOESmasked.normalizedDifference(['CMI_C03', 'CMI_C06']).toFloat().rename('NBR')
cloudMasked = goesImg.select('CMI_C03').updateMask(C_Mask).toFloat().rename('CC')
fireMasked = goesImg.select('CMI_C03').updateMask(F_Mask).toFloat().rename('FC')
return goesImg.addBands([NBRmasked,cloudMasked, fireMasked,QF_Mask,C_Mask])
'''Parameter Array Name Value Bit(s) = Value
Sun Glint QF1 Surface Reflectance None 6-7 = 00
Low Sun Mask QF1 Surface Reflectance High 5 = 0
Day/Night QF1 Surface Reflectance Day 4 =0
Cloud Detection QF1 Surface Reflectance Confident Clear 2-3 = 00 or Problably Clear 2-3 = 01
Cloud Mask Quality QF1 Surface Reflectance High or Medium 0-1 = 10 or 11
Snow/Ice QF2 Surface Reflectance No Snow or Ice 5 = 0
Cloud Shadow QF2 Surface Reflectance No Cloud Shadow 3 = 0
LandWater QF2 Surface Reflectance Land, Snow, Arctic, Antarctic or Greenland, Desert 0-2 = 011, 100, 101, 110, 111
Thin Cirrus Flag QF7 Surface Reflectance No Thin Cirrus 4 = 0
Aerosol Quantity QF7 Surface Reflectance Climatology, Low or Medium 2-3 = 00, 01 or 10
Adjacent to Cloud QF7 Surface Reflectance Not Adjacent to Cloud 1 = 0'''
def VcalcNBR (VIIRSimg):
QF1 = VIIRSimg.select('QF1').int()
QF2 = VIIRSimg.select('QF2').int()
QF7 = VIIRSimg.select('QF7').int()
QF_Mask = (QF1.bitwiseAnd(BitMask_3).eq(0)).And\
((QF2.bitwiseAnd(BitMask_2).eq(4)).Or((QF2.bitwiseAnd(BitMask_1).eq(0)))).And\
(QF2.bitwiseAnd(BitMask_5).eq(0)).rename('QFmask');
VIIRSm = VIIRSimg.select(['I2','M11']).updateMask(QF_Mask);
NBR = VIIRSm.normalizedDifference(['I2','M11']).toFloat().rename('NBR')
return VIIRSimg.addBands(NBR).addBands(QF_Mask)#.set('avgNBR', avgNBR)
''' Bit 1: Dilated Cloud
Bit 2: Cirrus (high confidence)
Bit 3: Cloud
Bit 4: Cloud Shadow
Bit 5: Snow
Bit 6: Clear (0: Cloud or Dilated Cloud bits are set, 1: Cloud and Dilated Cloud bits are not set)
Bit 7: Water
Bits 8-9: Cloud Confidence (0: None, 1: Low, 2: Medium, 3: High)
Bits 10-11: Cloud Shadow Confidence (0: None, 1: Low, 2: Medium, 3: High)
Bits 12-13: Snow/Ice Confidence (0: None, 1: Low, 2: Medium, 3: High)
Bits 14-15: Cirrus Confidence (0: None, 1: Low, 2: Medium, 3: High)'''
def LcalcNBR (LSimg):
QApixel = LSimg.select('QA_PIXEL').int()
QF_Mask =(QApixel.bitwiseAnd(BitMask_3).eq(0)).And\
(QApixel.bitwiseAnd(BitMask_5).eq(0)).And\
(QApixel.bitwiseAnd(BitMask_7).eq(0)).rename('QFmask');
LSmasked = LSimg.select(['SR_B5','SR_B7']).updateMask(QF_Mask);
NBR = LSmasked.normalizedDifference(['SR_B5','SR_B7']).toFloat().rename('NBR')
return LSimg.addBands(NBR).addBands(QF_Mask)#.set('avgNBR', avgNBR)
''' 1 Saturated or defective
2 Dark Area Pixels
3 Cloud Shadows
4 Vegetation
5 Bare Soils
6 Water
7 Clouds Low Probability / Unclassified
8 Clouds Medium Probability
9 Clouds High Probability
10 Cirrus
11 Snow / Ice'''
def ScalcNBR (sentImg):
SCL = sentImg.select('SCL');
QF_Mask =(SCL.neq(6)).And\
(SCL.neq(8)).And\
(SCL.neq(9)).And\
(SCL.neq(11))\
.rename('QFmask');
sentMasked = sentImg.select(['B8A','B12']).updateMask(QF_Mask); #B8 is another option- broadband NIR
NBR = sentMasked.normalizedDifference(['B8A','B12']).toFloat().rename('NBR')
return sentImg.addBands(NBR).addBands(QF_Mask).addBands(SCL)#.set('avgNBR', avgNBR)