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1312 | def imageProcessing(algo, productID, dateList, clip = True):
"""
Aplica um algoritmo as coleções de imagens para conseguir os dados espectrais
"""
global image_collection
global bands
global export_vars, export_bands
# Adicionado a partir dos objetos globais usados entre as funções
aoi = None
# Band dictio/lists:
bands = getSpectralBands(productID)
irBands = [bands[band] for band in ["wl740", "wl780", "wl800", "wl900", "wl1200", "wl1500", "wl2000"] if band in bands]
spectralBands = [PRODUCT_SPECS[productID]["bandList"][i] for i in PRODUCT_SPECS[productID]["spectralBandInds"]]
# Reference band:
refBand = PRODUCT_SPECS[productID]["scaleRefBand"]
# Lists of bands and variables which will be calculated and must be exported to the result data frame.
export_vars = ["img_time"]
export_bands = []
# Filter and prepare the image collection.
dateMin = dateList[0]
dateMax = (pd.Timestamp(dateList[-1])
+ pd.Timedelta(1, "day")).strftime("%Y-%m-%d")
image_collection = ee.ImageCollection(
getCollection(productID)
).filterBounds(aoi).filterDate(dateMin, dateMax)
# Set image date and time (manually set time for Modis products).
if productID in [101,103,105,111,113,115]:
image_collection = image_collection.map(
lambda image: image.set(
"img_date", ee.Image(image).date().format("YYYY-MM-dd"),
"img_time", "10:30"
))
elif productID in [102,104,106,112,114,116]:
image_collection = image_collection.map(
lambda image: image.set(
"img_date", ee.Image(image).date().format("YYYY-MM-dd"),
"img_time", "13:30"
))
elif productID in [107,117]:
image_collection = image_collection.map(
lambda image: image.set(
"img_date", ee.Image(image).date().format("YYYY-MM-dd"),
"img_time", "12:00"
))
else:
image_collection = image_collection.map(
lambda image: image.set(
"img_date", ee.Image(image).date().format("YYYY-MM-dd"),
"img_time", ee.Image(image).date().format("HH:mm")
))
image_collection = image_collection.filter(
ee.Filter.inList("img_date", dateList)
)
sortedCollection = image_collection.sort("img_date")
imageCollection_list = sortedCollection.toList(5000)
imgDates = ee.List(sortedCollection.aggregate_array("img_date"))
distinctDates = imgDates.distinct()
dateFreq = distinctDates.map(lambda d: imgDates.frequency(d))
# Function to be mapped to the image list and mosaic same-date images.
def oneImgPerDate(freq, imgList):
freq = ee.Number(freq)
localImgList = ee.List(imgList).slice(0, freq)
firstImg = ee.Image(localImgList.get(0))
properties = firstImg.toDictionary(
firstImg.propertyNames()
).remove(["system:footprint"], True)
proj = firstImg.select(refBand).projection()
#mosaic = ee.Image(qaMask_collection(productID, ee.ImageCollection(localImgList), True).qualityMosaic("qa_mask").setMulti(properties)).setDefaultProjection(proj).select(firstImg.bandNames())
mosaic = ee.Image(ee.ImageCollection(localImgList).reduce(
ee.Reducer.mean()).setMulti(
properties)).setDefaultProjection(proj).rename(
firstImg.bandNames()
)
singleImg = ee.Image(
ee.Algorithms.If(freq.gt(1), mosaic, firstImg)
)
return ee.List(imgList).splice(0, freq).add(singleImg)
mosaicImgList = ee.List(dateFreq.iterate(
oneImgPerDate, imageCollection_list)
)
mosaicCollection = ee.ImageCollection(
mosaicImgList).copyProperties(image_collection)
image_collection = ee.ImageCollection(
ee.Algorithms.If(imgDates.length().gt(distinctDates.length()),
mosaicCollection, image_collection)
)
# Clip the images.
if clip:
image_collection = image_collection.map(
lambda image: ee.Image(image).clip(aoi)
)
# Rescale the spectral bands.
def rescaleSpectralBands(image):
finalImage = image.multiply(
PRODUCT_SPECS[productID]["scalingFactor"]
).add(PRODUCT_SPECS[productID]["offset"]).copyProperties(image)
return finalImage
if (PRODUCT_SPECS[productID]["scalingFactor"]
and PRODUCT_SPECS[productID]["offset"]):
image_collection = image_collection.map(rescaleSpectralBands)
# Reusable functions:
# Set the number of unmasked pixels as an image property.
def nSelecPixels(image):
scale = image.select(refBand).projection().nominalScale()
nSelecPixels = image.select(
refBand).reduceRegion(
ee.Reducer.count(), aoi
).values().getNumber(0)
return image.set("n_selected_pixels", nSelecPixels)
# minNDVI clustering: select the cluster with the lowest NDVI.
def minNDVI(image):
nClusters = 20
targetBands = [bands["red"], bands["NIR"]]
redNIRimage = ee.Image(image).select(targetBands)
ndviImage = redNIRimage.normalizedDifference([bands["NIR"], bands["red"]])
# Make the training dataset for the clusterer.
trainingData = redNIRimage.sample()
clusterer = ee.Clusterer.wekaCascadeKMeans(2, nClusters).train(trainingData)
resultImage = redNIRimage.cluster(clusterer)
# Update the clusters (classes).
maxID = resultImage.reduceRegion(ee.Reducer.max(), aoi).values().getNumber(0)
clusterIDs = ee.List.sequence(0, maxID)
# Pick the class with the smallest NDVI.
ndviList = clusterIDs.map(
lambda id: ndviImage.updateMask(
resultImage.eq(ee.Image(ee.Number(id)))
).reduceRegion(
ee.Reducer.mean(), aoi
).values().getNumber(0)
)
minNDVI = ndviList.sort().getNumber(0)
waterClusterID = ndviList.indexOf(minNDVI)
return image.updateMask(resultImage.eq(waterClusterID))
# RICO algorithm.
def rico(image):
firstCut = image.updateMask(
image.select(bands["NIR"]).lt(2000).And(
image.select(bands["NIR"]).gte(0)
).And(image.select(bands["red"]).gte(0))
)
newRed = firstCut.select(bands["red"]).subtract(
firstCut.select(bands["NIR"])
).unitScale(-500,500).rename("R")
newGreen = firstCut.select(bands["NIR"]).unitScale(0,2000).rename("G")
newBlue = firstCut.select(bands["NIR"]).subtract(500).unitScale(0,1500).rename("B")
redwaterImg = newRed.addBands(newGreen).addBands(newBlue)
hsvImg = redwaterImg.rgbToHsv()
waterMask = hsvImg.select("hue").lt(0.08).selfMask()
value = hsvImg.select("value").updateMask(waterMask)
valueRef = value.reduceRegion(
reducer=ee.Reducer.median(), geometry=aoi, bestEffort=True
).values().getNumber(0)
statMask = ee.Image(ee.Algorithms.If(
valueRef, value.gte(valueRef.multiply(0.95)).And(
value.lte(valueRef.multiply(1.05))), waterMask
))
waterMask = waterMask.updateMask(statMask)
hsvImg = hsvImg.updateMask(statMask)
hue = hsvImg.select("hue")
saturation = hsvImg.select("saturation")
trustIndex = saturation.subtract(hue)
trustIndexRefs = trustIndex.reduceRegion(
reducer=ee.Reducer.percentile([40,95]), geometry=aoi,
bestEffort=True
).values()
trustIndexRef1 = trustIndexRefs.getNumber(0)
trustIndexRef2 = trustIndexRefs.getNumber(1)
sunglintMask = ee.Image(ee.Algorithms.If(
trustIndexRef1, trustIndex.gte(
trustIndexRef1).And(
trustIndex.gte(trustIndexRef2.multiply(0.8))
), waterMask
))
waterMask = waterMask.updateMask(sunglintMask)
return image.updateMask(waterMask)
# Statistic filter to remove mixed (outlier) pixels.
def mod3rStatFilter(image):
redNIRRatio = image.select(
bands["red"]).divide(image.select(bands["NIR"]).add(1)
)
redNIRRatioRef = redNIRRatio.reduceRegion(
reducer=ee.Reducer.median(), geometry=aoi
).values().getNumber(0)
statMask = ee.Image(ee.Algorithms.If(
redNIRRatioRef, redNIRRatio.gte(
redNIRRatioRef.multiply(0.95)
), image.mask())
)
return image.updateMask(statMask)
# Function to calculate a quality flag for Modis images.
def mod3rQualFlag(image):
tmpImage = image
tmpImage.set("qual_flag", 0)
nSelecPixels = ee.Number(image.get("n_selected_pixels"))
nValidPixels = ee.Number(image.get("n_valid_pixels"))
nTotalPixels = ee.Number(image.get("n_total_pixels"))
scale = image.select(refBand).projection().nominalScale()
meanVals = image.select(
[bands["red"], bands["NIR"]]
).reduceRegion(ee.Reducer.mean(), aoi).values()
redMean = meanVals.getNumber(0)
nirMean = meanVals.getNumber(1)
convrad = ee.Number(math.pi / 180)
if productID < 110 or productID in [151,152]:
vzen = image.select("SensorZenith").reduceRegion(
reducer=ee.Reducer.mean(), geometry=aoi, scale = scale
).getNumber("SensorZenith").divide(100).multiply(convrad)
szen = image.select("SolarZenith").reduceRegion(
reducer=ee.Reducer.mean(), geometry=aoi, scale=scale
).getNumber("SolarZenith").divide(100).multiply(convrad)
solaz = image.select("SolarAzimuth").reduceRegion(
reducer=ee.Reducer.mean(), geometry=aoi, scale=scale
).getNumber("SolarAzimuth").divide(100).multiply(convrad)
senaz = image.select("SensorAzimuth").reduceRegion(
reducer=ee.Reducer.mean(), geometry=aoi, scale=scale
).getNumber("SensorAzimuth").divide(100).multiply(convrad)
delta = solaz.subtract(senaz)
delta = ee.Number(ee.Algorithms.If(
delta.gte(360), delta.subtract(360), delta)
)
delta = ee.Number(ee.Algorithms.If(
delta.lt(0), delta.add(360), delta)
)
raz = delta.subtract(180).abs()
elif productID in range(111,120):
vzen = image.select("ViewZenith").reduceRegion(
reducer=ee.Reducer.mean(), geometry=aoi, scale=scale
).getNumber("ViewZenith").divide(100).multiply(convrad)
szen = image.select("SolarZenith").reduceRegion(
reducer=ee.Reducer.mean(), geometry=aoi, scale=scale
).getNumber("SolarZenith").divide(100).multiply(convrad)
raz = image.select("RelativeAzimuth").reduceRegion(
reducer=ee.Reducer.mean(), geometry=aoi, scale=scale
).getNumber("RelativeAzimuth").divide(100).multiply(convrad)
sunglint = vzen.cos().multiply(szen.cos()).subtract(
vzen.sin().multiply(szen.sin()).multiply(raz.cos())
).acos().divide(convrad)
sunglint = sunglint.min(ee.Number(180).subtract(sunglint))
qual = ee.Number(1).add( \
nValidPixels.divide(nTotalPixels).lt(0.05) \
.Or(nSelecPixels.divide(nValidPixels).lt(0.1)) \
.Or(nSelecPixels.lt(10)) \
).add( \
vzen.divide(convrad).gte(45) \
.Or(sunglint.lte(25)) \
).add( \
nirMean.gte(1000) \
.Or(nirMean.subtract(redMean).gte(300)) \
.add(nirMean.gte(2000).multiply(2)) \
)
image = image.set(
"vzen", vzen.divide(convrad), "sunglint",
sunglint, "qual_flag", qual.min(3)
)
image = ee.Image(ee.Algorithms.If(
nSelecPixels.gt(0), image, tmpImage)
)
return image;
# Calculates a quality flag for algorithms that distinguish
# the numbers of total, valid, water and selected pixels,
# such as the S2WP algorithms.
def s2wpQualFlag(image):
nSelecPixels = ee.Number(image.get("n_selected_pixels"))
nWaterPixels = ee.Number(image.get("n_water_pixels"))
nValidPixels = ee.Number(image.get("n_valid_pixels"))
nTotalPixels = ee.Number(image.get("n_total_pixels"))
qualFlag = ee.Number(1).add( \
nValidPixels.divide(nTotalPixels).lt(0.2) \
).add( \
nSelecPixels.divide(nWaterPixels).lt(0.2) \
).add( \
nSelecPixels.divide(nWaterPixels).lt(0.01) \
).min(3).multiply(nSelecPixels.min(1))
return image.set("qual_flag", qualFlag)
# Calculates a generic quality flag.
def genericQualFlag(image):
nSelecPixels = ee.Number(image.get("n_selected_pixels"))
nValidPixels = ee.Number(image.get("n_valid_pixels"))
nTotalPixels = ee.Number(image.get("n_total_pixels"))
qualFlag = ee.Number(1).add( \
nValidPixels.divide(nTotalPixels).lt(0.2) \
).add( \
nSelecPixels.divide(nValidPixels).lt(0.1) \
).add( \
nSelecPixels.divide(nValidPixels).lt(0.01) \
).min(3).multiply(nSelecPixels.min(1))
return image.set("qual_flag", qualFlag)
# Algorithms:
# 00 is the most simple one. It does nothing to the images.
if algo == 0:
pass
# Simply removes pixels with cloud, cloud shadow or high aerosol.
if algo == 1:
image_collection = qaMask_collection(
productID, image_collection
)
# MOD3R and its variations
elif algo in [2, 3, 4]:
export_vars = list(set(export_vars).union({
"n_selected_pixels", "n_valid_pixels",
"n_total_pixels", "vzen",
"sunglint", "qual_flag"}
)
)
# Set the number of total pixels and remove unlinkely water pixels.
image_collection = image_collection.map(
lambda image: ee.Image(image).set(
"n_total_pixels", ee.Image(image).select(
bands["red"]
).reduceRegion(
ee.Reducer.count(), aoi
).values().getNumber(0)
).updateMask(ee.Image(image).select(
bands["red"]).gte(0).And(
ee.Image(image).select(bands["red"]).lt(3000)
).And(ee.Image(image).select(bands["NIR"]).gte(0)
)
)
)
# Remove bad pixels (cloud, cloud shadow, high aerosol and
# acquisition/processing issues)
image_collection = qaMask_collection(productID, image_collection)
# Filter out images with too few valid pixels.
image_collection = image_collection.map(
lambda image: ee.Image(image).set(
"n_valid_pixels", ee.Image(image).select(
bands["red"]
).reduceRegion(
ee.Reducer.count(), aoi
).values().getNumber(0)
)
)
image_collection_out = ee.ImageCollection(
image_collection.filterMetadata(
"n_valid_pixels", "less_than", 10
).map(
lambda image: ee.Image(image).set(
"n_selected_pixels", 0,
"qual_flag", 0
).updateMask(ee.Image(0))
)
)
image_collection_in = ee.ImageCollection(
image_collection.filterMetadata(
"n_valid_pixels", "greater_than", 9
)
)
if algo == 2:
# MOD3R clusterer/cassifier.
## Run k-means with up to 5 clusters and choose the cluster
# which most likley represents water.
## For such choice, first define the cluster which probably
# represents soil or vegetation.
## Such cluster is the one with the largest difference
# between red and NIR.
## Then test every other cluster as a possible water endmember,
# choosing the one which yields the smaller error.
def mod3r(image):
nClusters = 20
targetBands = [bands["red"], bands["NIR"]]
redNIRimage = ee.Image(image).select(targetBands)
# Make the training dataset for the clusterer.
trainingData = redNIRimage.sample()
clusterer = ee.Clusterer.wekaCascadeKMeans(
2, nClusters).train(trainingData)
resultImage = redNIRimage.cluster(clusterer)
# Update the clusters (classes).
maxID = ee.Image(resultImage).reduceRegion(
ee.Reducer.max(), aoi).values().get(0)
clusterIDs = ee.List.sequence(0, ee.Number(maxID))
# Get the mean band values for each cluster.
clusterBandVals = clusterIDs.map(
lambda id: redNIRimage.updateMask(
resultImage.eq(ee.Image(ee.Number(id)))
).reduceRegion(ee.Reducer.mean(), aoi)
)
# Get a red-NIR difference list.
redNIRDiffList = clusterBandVals.map(
lambda vals: ee.Number(
ee.Dictionary(vals).get(bands["NIR"])
).subtract(
ee.Number(ee.Dictionary(vals).get(bands["red"]))
)
)
# Pick the class with the greatest difference to be the land endmember.
greatestDiff = redNIRDiffList.sort().reverse().get(0)
landClusterID = redNIRDiffList.indexOf(greatestDiff)
# The other clusters are candidates for water endmembers.
waterCandidateIDs = clusterIDs.splice(landClusterID, 1)
# Apply, for every water candidate cluster, an unmix
# procedure with non-negative-values constraints.
# Then choose as water representative the one which
# yielded the smaller prediction error.
landEndmember = ee.Dictionary(clusterBandVals.get(
landClusterID
)).values(targetBands)
landEndmember_red = ee.Number(landEndmember.get(0))
landEndmember_nir = ee.Number(landEndmember.get(1))
landImage = ee.Image(landEndmember_red).addBands(
ee.Image(landEndmember_nir)
).rename(targetBands)
minError = ee.Dictionary().set(
"id", ee.Number(waterCandidateIDs.get(0))
).set("val", ee.Number(2147483647)
)
# Function for getting the best water candidate.
def pickWaterCluster(id, errorDict):
candidateWaterEndmember = ee.Dictionary(
clusterBandVals.get(ee.Number(id))
).values(targetBands)
candidateWaterEndmember_red = ee.Number(
candidateWaterEndmember.get(0)
)
candidateWaterEndmember_nir = ee.Number(
candidateWaterEndmember.get(1)
)
candidateWaterImage = ee.Image(
candidateWaterEndmember_red
).addBands(
ee.Image(candidateWaterEndmember_nir)
).rename(targetBands)
otherCandidatesIDs = waterCandidateIDs.splice(
ee.Number(id), 1
)
def testCluster(otherID, accum):
maskedImage = redNIRimage.updateMask(
resultImage.eq(ee.Number(otherID))
)
fractions = maskedImage.unmix([
landEndmember, candidateWaterEndmember],
True, True
)
predicted = landImage.multiply(
fractions.select("band_0")
).add(candidateWaterImage.multiply(
fractions.select("band_1"))
)
return ee.Number(
maskedImage.subtract(
predicted
).pow(2).reduce(
ee.Reducer.sum()
).reduceRegion(
ee.Reducer.mean(), aoi
).values().get(0)).add(ee.Number(accum)
)
errorSum = otherCandidatesIDs.iterate(testCluster, 0)
errorDict = ee.Dictionary(errorDict)
prevError = ee.Number(errorDict.get("val"))
prevID = ee.Number(errorDict.get("id"))
newError = ee.Algorithms.If(
ee.Number(errorSum).lt(prevError), errorSum, prevError
)
newID = ee.Algorithms.If(
ee.Number(errorSum).lt(prevError), ee.Number(id), prevID
)
return errorDict.set(
"id", newID).set("val", newError)
waterClusterID = ee.Number(
ee.Dictionary(
waterCandidateIDs.iterate(
pickWaterCluster, minError)).get("id")
)
# Return the image with non-water clusters masked,
# with the clustering result as a band and with the water
# cluster ID as a property.
return image.updateMask(
resultImage.eq(
ee.Image(waterClusterID))
)
elif algo == 3:
# minNDVI: a MOD3R modification. Get the lowest-NDVI cluster.
mod3r = minNDVI
elif algo == 4:
# minNIR: a MOD3R modification. Get the lowest-NIR cluster.
def mod3r(image):
nClusters = 20
targetBands = [bands["red"], bands["NIR"]]
redNIRimage = ee.Image(image).select(targetBands)
# Make the training dataset for the clusterer.
trainingData = redNIRimage.sample()
clusterer = ee.Clusterer.wekaCascadeKMeans(
2, nClusters).train(trainingData)
resultImage = redNIRimage.cluster(clusterer)
# Update the clusters (classes).
maxID = resultImage.reduceRegion(ee.Reducer.max(), aoi).values().getNumber(0)
clusterIDs = ee.List.sequence(0, maxID)
# Pick the class with the smallest NDVI.
nirList = clusterIDs.map(
lambda id: redNIRimage.select(
bands["NIR"]).updateMask(resultImage.eq(
ee.Image(ee.Number(id))
)
).reduceRegion(
ee.Reducer.mean(), aoi
).values().getNumber(0)
)
minNIR = nirList.sort().getNumber(0)
waterClusterID = nirList.indexOf(minNIR)
return ee.Image(image).updateMask(
resultImage.eq(waterClusterID)
)
# Run the modified MOD3R algorithm and set the quality flag.
image_collection_in = image_collection_in.map(mod3r) \
.map(mod3rStatFilter) \
.map(nSelecPixels) \
.map(mod3rQualFlag)
# Reinsert the unprocessed images.
image_collection = ee.ImageCollection(
image_collection_in.merge(image_collection_out)
).copyProperties(image_collection)
# Ventura 2018 (Açudes)
elif algo == 5:
# Remove bad pixels (cloud, cloud shadow, high aerosol and
# acquisition/processing issues)
image_collection = qaMask_collection(productID, image_collection)
# Remove pixels with NIR > 400.
image_collection = ee.ImageCollection(image_collection).map(
lambda image: ee.Image(image).updateMask(
ee.Image(image).select(bands["NIR"]).lte(400).And(
ee.Image(image).select(bands["NIR"]).gte(0))
)
)
# Sentinel-2 Water Processing (S2WP) algorithm version 6.
elif algo in [6, 7, 8]:
export_vars = list(set(export_vars).union({"n_selected_pixels"}))
def s2wp6(image):
blue = image.select(bands["blue"])
green = image.select(bands["green"])
nir = image.select(bands["NIR"])
swir2 = image.select(bands["wl2000"])
minSWIR = image.select(
[bands["wl1500"],bands["wl2000"]]
).reduce(ee.Reducer.min())
maxGR = image.select(
[bands["green"], bands["red"]]
).reduce(ee.Reducer.max())
blueNIRratio = blue.divide(nir)
b1pred = blue.multiply(1.1470590).add(
green.multiply(-0.24835489)
).add(38.96482)
vis = image.select([bands["blue"], bands["green"], bands["red"]])
maxV = vis.reduce(ee.Reducer.max())
minV = vis.reduce(ee.Reducer.min())
maxDiffV = maxV.subtract(minV)
ndwi = image.normalizedDifference([bands["green"], bands["NIR"]])
ci = image.normalizedDifference([bands["red"], bands["green"]])
rg = image.select(bands["red"]).divide(image.select(bands["green"]))
ndwihvt2 = maxGR.addBands(minSWIR).normalizedDifference()
aeib2 = maxDiffV.subtract(blue)
aeib1 = maxDiffV.subtract(b1pred)
nirMaxVratio = nir.divide(maxV)
predNIRmaxVratioHighR = rg.multiply(1.45589130421).exp().multiply(0.0636397716305)
nirMaxVratioDevHighR = nirMaxVratio.subtract(predNIRmaxVratioHighR)
image = image.updateMask(ndwihvt2.gte(0).And(minSWIR.lt(420)))
darkAndInterW = maxDiffV.lt(250) \
.And(nir.lt(300)) \
.And(aeib2.gte(-450)) \
.And(maxDiffV.gte(120) \
.And(swir2.lt(125)) \
.Or(ci.lt(0.08).And(swir2.lt(60)))) \
.And(ndwihvt2.gte(0.78) \
.Or(aeib2.subtract(ci.polynomial(
[-151.17, -359.17])).abs().lt(80)))
darkW = darkAndInterW.And(maxDiffV.lt(120))
interW = darkAndInterW.And(maxDiffV.gte(120).And(maxDiffV.lt(250)))
brightW = interW.Or(maxDiffV.gte(220) \
.And(aeib2.gte(-350)) \
.And(ndwihvt2.gte(0.4)) \
.And(nirMaxVratioDevHighR.lt(0.5)) \
.And(ndwi.gte(-0.1).Or(maxDiffV.gte(420).And(ci.gte(0.3).Or(maxDiffV.gte(715))))) \
.And(ci.lt(0.23).And(aeib2.gte(
ci.polynomial([-881.33, 5266.7])
)).Or(ci.gte(0.23).And(aeib2.gte(ci.polynomial([519.41, -823.53])))))
.And( \
ci.lt(-0.35).And(ndwihvt2.gte(0.78).Or(aeib1.gte(-5)).Or(blueNIRratio.gte(4))) \
.Or(ci.gte(-0.35).And(ci.lt(-0.2)).And(
ndwihvt2.gte(0.78).Or(aeib1.gte(-15)).Or(blueNIRratio.gte(5)))) \
.Or(ci.gte(-0.2).And(ci.lt(0.3)).And(ndwihvt2.gte(0.78).Or(aeib1.gte(0)))) \
.Or(ci.gte(0.3).And(aeib2.gte(220))) \
) \
)
# Bright + dark waters:
if algo == 6:
image = image.updateMask(darkW.Or(brightW))
# Only bright waters:
elif algo == 7:
image = image.updateMask(brightW)
# Only dark waters:
elif algo == 8:
image = image.updateMask(darkW)
return image.set("n_selected_pixels", image.select(
bands["red"]).reduceRegion(
ee.Reducer.count(), aoi).values().get(0))
image_collection = image_collection.map(s2wp6)
# Sentinel-2 Water Processing (S2WP) algorithm versions 7 and 8.
elif algo in [9,10,12]:
export_vars = list(set(export_vars).union({
"n_selected_pixels", "n_valid_pixels",
"n_total_pixels", "n_water_pixels",
"qual_flag"}
)
)
# Set the total number of pixels in the aoi as an image property:
def totalPixels(image):
scale = image.select(refBand).projection().nominalScale()
return image.set(
"n_total_pixels", image.select(refBand).reduceRegion(
ee.Reducer.count(), aoi, scale
).values().getNumber(0)
)
image_collection = image_collection.map(totalPixels)
# Mask clouds and set the number of valid (non-cloudy) pixels.
def validPixels(image):
vis = image.select([
bands["blue"], bands["green"], bands["red"]]
)
maxV = vis.reduce(ee.Reducer.max())
minV = vis.reduce(ee.Reducer.min())
maxDiffV = maxV.subtract(minV)
atmIndex = maxDiffV.subtract(minV)
# Exclude cloud pixels (it will inadvertedly pick very bright pixels):
validPixels = atmIndex.gte(-1150)
image = image.updateMask(validPixels)
scale = image.select(refBand).projection().nominalScale()
nValidPixels = image.select(refBand).reduceRegion(
ee.Reducer.count(), aoi, scale
).values().getNumber(0)
return image.set("n_valid_pixels", nValidPixels)
image_collection = image_collection.map(validPixels)
# Select potential water pixels.
def waterPixels(image):
swir1 = image.select(bands["wl1500"])
swir2 = image.select(bands["wl2000"])
ndwihvt = image.select(bands["green"]).max(
image.select(bands["red"])
).addBands(swir2).normalizedDifference()
waterMask = ndwihvt.gte(0).And(swir1.lt(680))
scale = image.select(refBand).projection().nominalScale()
nWaterPixels = waterMask.reduceRegion(
ee.Reducer.count(), aoi, scale
).values().getNumber(0)
return image.updateMask(waterMask).set("n_water_pixels", nWaterPixels)
image_collection = image_collection.map(waterPixels)
# Remove border (spectrally mixed) pixels (only work for Sentinel-2).
# "B8" in bands.values() and "B8A" in bands.values():
if productID in [201,151,152]:
if productID == 201:
def maskBorder(image):
smi = image.normalizedDifference(["B8","B8A"])
return image.updateMask(smi.abs().lt(0.2))
else:
def maskBorder(image):
smi = image.select("I3").divide(image.select("M10"))
return image.updateMask(smi.lte(1))
image_collection = image_collection.map(maskBorder)
if algo == 9:
# More appropriate for Sentinel-2 and Landsat:
nir_thr = 2000
blue_thr = 2000
ndwihvt_thr_bright = 0.2
ndwi_thr_dark = -0.15
maxOffset = 30
elif algo == 10:
# More appropriate for MODIS:
nir_thr = 1500
blue_thr = 800
ndwihvt_thr_bright = 0.4
ndwi_thr_dark = 0
maxOffset = 0
# Algorithm - version 7.
def s2wp7(image):
swir2 = image.select(bands["wl2000"])
vnir = image.select([
bands["blue"], bands["green"],
bands["red"], bands["NIR"]]
)
offset = vnir.reduce(ee.Reducer.min()).min(0).abs()
blue = image.select(bands["blue"]).add(offset)
green = image.select(bands["green"]).add(offset)
red = image.select(bands["red"]).add(offset)
nir = image.select(bands["NIR"]).add(offset)
vnir_offset = blue.addBands(green).addBands(red).addBands(nir)
vis = vnir_offset.select(
[bands["blue"], bands["green"],
bands["red"]]
)
minV = vis.reduce(ee.Reducer.min())
maxV = vis.reduce(ee.Reducer.max())
maxDiffV = maxV.subtract(minV)
ci = vnir_offset.normalizedDifference(
[bands["red"], bands["green"]]
)
ndwi = vnir_offset.normalizedDifference(
[bands["green"], bands["NIR"]]
)
ngbdi = vnir_offset.normalizedDifference(
[bands["green"], bands["blue"]]
)
ndwihvt = green.max(red).addBands(swir2).normalizedDifference()
# An index helpful to detect clouds (+ bright pixels), cirrus and aerosol:
saturationIndex = maxDiffV.subtract(minV)
# CI-Saturation Index curves.
curveCI_SI1 = ci.polynomial([-370, -800])
curveCI_SI2 = -290
curveCI_SI3 = ci.polynomial([-378.57, 1771.4])
# A visible-spectrum-based filter which removes pixels strongly
# affected by aerosol, sungling and cirrus.
saturationFilter = saturationIndex.gte(curveCI_SI1).And(
saturationIndex.gte(curveCI_SI2)).And(
saturationIndex.gte(curveCI_SI3))
# CI-NDWI curves to detect sunglint and cirrus:
curveHighR1a = ci.polynomial([0.745, 0.575])
curveHighR1b = ci.polynomial([0.3115, -1.5926])
curveHighR1c = ci.polynomial([0.4158, -3.0833])
curveLowR1 = ci.polynomial([-0.3875, -2.9688])
# A visible & infrared filter for sunglint, cirrus and dark land pixels.
# The filter is applied separately to low and high reflectance pixels.
multiFilter = maxV.gte(200).And(
ndwihvt.gte(ndwihvt_thr_bright).And(
ndwi.gte(0.6).Or(
ndwi.gte(curveHighR1a)).Or(
ndwi.gte(curveHighR1b)
).Or(ndwi.gte(curveHighR1c)
).Or(ngbdi.gte(0.25).And(
ndwihvt.gte(0.7)
)))
).Or(maxV.lt(250).And(
ndwi.gte(ndwi_thr_dark).And(
ndwi.gte(curveLowR1)).Or(
ndwi.gte(0.6)))
)
# "Good" water pixels:
waterMask = saturationFilter.And(
multiFilter).And(
nir.lt(nir_thr)).And(
blue.lt(blue_thr)).And(
offset.lte(maxOffset)
).selfMask()
# Filter shadow by comparing each pixel to the median of the
# area of interest.
# It must be applied to a small water surface area so to
# avoid shadow misclassification due to heterogeneity.
shadowFilter = waterMask
indicator = maxV.updateMask(waterMask)
indicator_ref = indicator.reduceRegion(
reducer = ee.Reducer.median(), geometry = aoi,
bestEffort = True
).values().getNumber(0)
proportionToRef = indicator.divide(indicator_ref);
shadowFilter = ee.Image(ee.Algorithms.If(
indicator_ref, proportionToRef.gte(0.8), shadowFilter)
)
waterMask = waterMask.updateMask(shadowFilter)
return image.updateMask(waterMask)
# Algorithm - version 8.2
def s2wp8(image):
# Bands and indices:
blue = image.select(bands["blue"])
green = image.select(bands["green"])
red = image.select(bands["red"])
nir = image.select(bands["NIR"])
swir2 = image.select(bands["wl2000"])
vis = image.select([
bands["blue"], bands["green"], bands["red"]]
)
minV = vis.reduce(ee.Reducer.min())
maxV = vis.reduce(ee.Reducer.max())
maxDiffV = maxV.subtract(minV)
ci = image.normalizedDifference([bands["red"],bands["green"]])
ndwihvt = green.max(red).addBands(swir2).normalizedDifference()
# Remove negative-reflectance pixels.
ndwihvt = ndwihvt.updateMask(minV.gte(0).And(nir.gte(0)))
# Atmospheric Index (for detection of cloud, cirrus and aerosol).
atmIndex2 = green.subtract(blue.multiply(2))
# Filter pixels affected by glint, cirrus or aerosol.
atm2ndwihvtMask = atmIndex2.gte(ndwihvt.multiply(-500).add(100))
# "Good" water pixels:
waterMask = atm2ndwihvtMask.And(ndwihvt.gte(0.6)).selfMask()
# Filter shaded pixels statistically. For it to work
# properly, the water must be homogeneous.
shadowFilter = waterMask
indicator = maxV.updateMask(waterMask)
indicator_ref = indicator.reduceRegion(
reducer = ee.Reducer.median(),
geometry = aoi, bestEffort = True
).values().getNumber(0)
proportionToRef = indicator.divide(indicator_ref)
shadowFilter = ee.Image(ee.Algorithms.If(
indicator_ref, proportionToRef.gte(0.5), shadowFilter)
)
# Final mask:
waterMask = waterMask.updateMask(shadowFilter)
return image.updateMask(waterMask)
if algo in [9,10]:
image_collection = image_collection.map(s2wp7)
elif algo == 12:
image_collection = image_collection.map(s2wp8)
# Set the final number of pixels as an image property:
def selecPixels(image):
scale = image.select(refBand).projection().nominalScale()
return image.set(
"n_selected_pixels", image.select(refBand)
.reduceRegion(
ee.Reducer.count(), aoi, scale
).values().getNumber(0)
)
image_collection = image_collection.map(selecPixels)
image_collection = image_collection.map(s2wpQualFlag) # Quality flag.
# RICO (Red In Cyan Out)
elif algo == 11:
if(productID < 200 and not productID in [103,104,113,114]):
export_vars = list(set(export_vars).union({
"n_selected_pixels", "n_valid_pixels",
"n_total_pixels", "vzen",
"sunglint", "qual_flag"}
)
)
else:
export_vars = list(set(export_vars).union({
"n_selected_pixels", "n_valid_pixels",
"n_total_pixels", "qual_flag"}
)
)
# Set the number of total pixels.
image_collection = image_collection.map(
lambda image: image.set(
"n_total_pixels", image.select(refBand).reduceRegion(
ee.Reducer.count(), aoi).values().getNumber(0)
)
)
# Mask bad pixels.
image_collection = qaMask_collection(productID, image_collection)
# Set the number of valid (remainging) pixels.
image_collection = image_collection.map(
lambda image: image.set(
"n_valid_pixels", image.select(refBand).reduceRegion(
ee.Reducer.count(), aoi).values().getNumber(0)
)
)
# Apply the algorithm.
image_collection = image_collection.map(rico).map(nSelecPixels)
# Filter images with no good pixels.
image_collection_out = ee.ImageCollection(
image_collection.filterMetadata(
"n_selected_pixels", "less_than", 1
).map(lambda image: ee.Image(image).set(
"n_selected_pixels", 0,
"qual_flag", 0).updateMask(ee.Image(0))
)
)
image_collection_in = ee.ImageCollection(
image_collection.filterMetadata("n_selected_pixels", "greater_than", 0)
)
# Quality flag:
if(productID < 200 and not productID in [103,104,113,114]):
image_collection_in = image_collection_in.map(mod3rQualFlag)
else:
image_collection_in = image_collection_in.map(
genericQualFlag
)
# Reinsert the unprocessed images.
image_collection = ee.ImageCollection(
image_collection_in.merge(image_collection_out)
).copyProperties(image_collection)
# minNDVI + Wang et al. 2016
elif algo == 13:
if(productID < 200 and not productID in [103,104,113,114]):
export_vars = list(set(export_vars).union({
"n_selected_pixels", "n_valid_pixels",
"n_total_pixels", "vzen","sunglint",
"qual_flag"}
)
)
else:
export_vars = list(set(export_vars).union({
"n_selected_pixels", "n_valid_pixels",
"n_total_pixels", "qual_flag"}
))
# Set the number of total pixels and remove unlinkely water pixels.
image_collection = image_collection.map( \
lambda image: ee.Image(image) \
.set("n_total_pixels", ee.Image(image).select(refBand)
.reduceRegion(ee.Reducer.count(), aoi)
.values().getNumber(0)) \
.updateMask( \
ee.Image(image).select(bands["red"]).gte(0) \
.And(ee.Image(image).select(bands["red"]).lt(3000)) \
.And(ee.Image(image).select(bands["NIR"]).gte(0)) \
) \
)
# Remove bad pixels (cloud, cloud shadow, high aerosol and acquisition/processing issues)
image_collection = qaMask_collection(productID, image_collection)
# Filter out images with too few valid pixels.
image_collection = image_collection.map(
lambda image: ee.Image(image) \
.set("n_valid_pixels", ee.Image(image)
.select(refBand).reduceRegion(
ee.Reducer.count(), aoi).values().getNumber(0)
)
)
image_collection_out = ee.ImageCollection(
image_collection.filterMetadata(
"n_valid_pixels", "less_than", 10).map(
lambda image: ee.Image(image).set(
"n_selected_pixels", 0, "qual_flag", 0
).updateMask(ee.Image(0)))
)
image_collection_in = ee.ImageCollection(
image_collection.filterMetadata(
"n_valid_pixels", "greater_than", 9)
)
# Clustering.
image_collection_in = image_collection_in.map(minNDVI)
def wang2016(image):
allBands = image.bandNames()
noCorrBands = allBands.removeAll(ee.List(spectralBands))
image = image.updateMask(image.select(spectralBands)
.reduce(ee.Reducer.min()).gte(0)) # Mask negative pixels
minIR = image.select(irBands).reduce(ee.Reducer.min())
vis = image.select([bands["blue"], bands["green"], bands["red"]])
minV = vis.reduce(ee.Reducer.min())
maxV = vis.reduce(ee.Reducer.max())
image = image.updateMask(minV.gte(minIR))
corrImage = image.select(
spectralBands).subtract(minIR).rename(spectralBands)
finalImage = ee.Image(corrImage.addBands(
image.select(noCorrBands)).copyProperties(image)
)
return finalImage
image_collection_in = image_collection_in.map(wang2016).map(nSelecPixels)
# Update the separate collections:
image_collection_out = ee.ImageCollection(
image_collection_out.merge(ee.ImageCollection(
image_collection_in.filterMetadata(
"n_selected_pixels", "less_than", 1)
).map(
lambda image: ee.Image(image).set(
"n_selected_pixels", 0, "qual_flag", 0).updateMask(
ee.Image(0))
).copyProperties(image_collection)
)
)
image_collection_in = ee.ImageCollection(
image_collection_in.filterMetadata(
"n_selected_pixels", "greater_than", 0)
)
# Quality flag:
if(productID < 200 and not productID in [103,104,113,114]):
image_collection_in = image_collection_in.map(
mod3rQualFlag
)
else:
image_collection_in = image_collection_in.map(
genericQualFlag
)
# Reinsert the unprocessed images.
image_collection = ee.ImageCollection(
image_collection_in.merge(image_collection_out)
).copyProperties(image_collection)
# GPM daily precipitation
elif algo == 14:
export_vars = list(set(export_vars).union(
{"n_selected_pixels", "area"})
)
area = aoi.area()
image_collection = image_collection.map(
nSelecPixels).map(
lambda image: ee.Image(image).set("area", ee.Number(area))
)
#---
# If not already added, add the final number of pixels selected
# by the algorithm as an image propoerty.
if not "n_selected_pixels" in export_vars:
export_vars.append("n_selected_pixels")
image_collection = image_collection.map(
lambda image: image.set(
"n_selected_pixels", image.select(refBand).reduceRegion(
ee.Reducer.count(), aoi,
image.select(
refBand).projection().nominalScale()
).values().getNumber(0)
)
)
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