F31a Checkpoint

Import libraries¶

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import ee
import geemap

import ee import geemap

Create an interactive map¶

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Map = geemap.Map(center=[40, -100], zoom=4)

Map = geemap.Map(center=[40, -100], zoom=4)

Add Earth Engine Python script¶

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# Add Earth Engine dataset
image = ee.Image("USGS/SRTMGL1_003")

#  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#  Chapter:      F3.1 Advanced Pixel-Based Image Transformations
#  Checkpoint:   F31a
#  Authors:      Karen, Andrea, Nick, and David
#  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# Import and filter imagery by location and date.
sfoPoint = ee.Geometry.Point(-122.3774, 37.6194)

sfoImage = ee.ImageCollection('COPERNICUS/S2') \
    .filterBounds(sfoPoint) \
    .filterDate('2020-02-01', '2020-04-01') \
    .first()
Map.centerObject(sfoImage, 11)

# Calculate EVI using Sentinel 2

# Extract the bands and divide by 10,000 to account for scaling done.
nirScaled = sfoImage.select('B8').divide(10000)
redScaled = sfoImage.select('B4').divide(10000)
blueScaled = sfoImage.select('B2').divide(10000)

# Calculate the numerator, note that order goes from left to right.
numeratorEVI = (nirScaled.subtract(redScaled)).multiply(2.5)

# Calculate the denominator.
denomClause1 = redScaled.multiply(6)
denomClause2 = blueScaled.multiply(7.5)
denominatorEVI = nirScaled.add(denomClause1) \
    .subtract(denomClause2).add(1)

# Calculate EVI and name it.
EVI = numeratorEVI.divide(denominatorEVI).rename('EVI')

# And now map EVI using our vegetation palette.
vegPalette = ['red', 'white', 'green']
visParams = {'min': -1, 'max': 1, 'palette': vegPalette}
	Map.addLayer(EVI, visParams, 'EVI')

# Calculate EVI.
eviExpression = sfoImage.expression({
    'expression': '2.5 * ((NIR - RED) / (NIR + 6 * RED - 7.5 * BLUE + 1))',
    'map': { # Map between variables in the expression and images.
        'NIR': sfoImage.select('B8').divide(10000),
        'RED': sfoImage.select('B4').divide(10000),
        'BLUE': sfoImage.select('B2').divide(10000)
    }
})

# And now map EVI using our vegetation palette.
Map.addLayer(eviExpression, visParams, 'EVI Expression')

#  -----------------------------------------------------------------------
#  CHECKPOINT
#  -----------------------------------------------------------------------

# Add Earth Engine dataset image = ee.Image("USGS/SRTMGL1_003") # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # Chapter: F3.1 Advanced Pixel-Based Image Transformations # Checkpoint: F31a # Authors: Karen, Andrea, Nick, and David # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # Import and filter imagery by location and date. sfoPoint = ee.Geometry.Point(-122.3774, 37.6194) sfoImage = ee.ImageCollection('COPERNICUS/S2') \ .filterBounds(sfoPoint) \ .filterDate('2020-02-01', '2020-04-01') \ .first() Map.centerObject(sfoImage, 11) # Calculate EVI using Sentinel 2 # Extract the bands and divide by 10,000 to account for scaling done. nirScaled = sfoImage.select('B8').divide(10000) redScaled = sfoImage.select('B4').divide(10000) blueScaled = sfoImage.select('B2').divide(10000) # Calculate the numerator, note that order goes from left to right. numeratorEVI = (nirScaled.subtract(redScaled)).multiply(2.5) # Calculate the denominator. denomClause1 = redScaled.multiply(6) denomClause2 = blueScaled.multiply(7.5) denominatorEVI = nirScaled.add(denomClause1) \ .subtract(denomClause2).add(1) # Calculate EVI and name it. EVI = numeratorEVI.divide(denominatorEVI).rename('EVI') # And now map EVI using our vegetation palette. vegPalette = ['red', 'white', 'green'] visParams = {'min': -1, 'max': 1, 'palette': vegPalette} Map.addLayer(EVI, visParams, 'EVI') # Calculate EVI. eviExpression = sfoImage.expression({ 'expression': '2.5 * ((NIR - RED) / (NIR + 6 * RED - 7.5 * BLUE + 1))', 'map': { # Map between variables in the expression and images. 'NIR': sfoImage.select('B8').divide(10000), 'RED': sfoImage.select('B4').divide(10000), 'BLUE': sfoImage.select('B2').divide(10000) } }) # And now map EVI using our vegetation palette. Map.addLayer(eviExpression, visParams, 'EVI Expression') # ----------------------------------------------------------------------- # CHECKPOINT # -----------------------------------------------------------------------

Display the interactive map¶

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Map

Map