A33a 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:      A3.3 Mangroves II - Change Mapping
#  Checkpoint:   A33a
#  Authors:      Celio de Sousa, David Lagomasino, and Lola Fatoyinbo
#  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# STEP 1 - ADD THE MAPS
areaOfstudy = ee.FeatureCollection("projects/gee-book/assets/A3-3/Border5km")
mangrove2000 = ee.Image("projects/gee-book/assets/A3-3/MangroveGuinea2000_v2")
mangrove2020 = ee.Image("projects/gee-book/assets/A3-3/MangroveGuinea2020_v2")

Map.setCenter(-13.6007, 9.6295, 10)
# Sets the map center to Conakry, Guinea
Map.addLayer(areaOfstudy, {}, "Area of Study")
Map.addLayer(mangrove2000, {"palette": "#16a596"}, "Mangrove Extent 2000")
Map.addLayer(mangrove2020, {"palette": "#9ad3bc"}, "Mangrove Extent 2020")

# STEP 2 -  MAP TO MAP CHANGE

mang2020 = mangrove2020.unmask(0)
mang2000 = mangrove2000.unmask(0)
change = mang2020.subtract(mang2000).clip(areaOfstudy)

paletteCHANGE = [
    "red",  # Loss/conversion
    "white",  # No Change
    "green",  # Gain/Expansion
]

Map.addLayer(
    change, {"min": -1, "max": 1, "palette": paletteCHANGE}, "Changes 2000-2020"
)

# Calculate the area of each pixel
gain = change.eq(1)
loss = change.eq(-1)

gainArea = gain.multiply(ee.Image.pixelArea().divide(1000000))
lossArea = loss.multiply(ee.Image.pixelArea().divide(1000000))

# Sum all the areas
statsgain = gainArea.reduceRegion(
    {"reducer": ee.Reducer.sum(), "scale": 30, "maxPixels": 1e14}
)

statsloss = lossArea.reduceRegion(
    {"reducer": ee.Reducer.sum(), "scale": 30, "maxPixels": 1e14}
)

print(statsgain.get("classification"), "km² of new mangroves in 2020")
print(statsloss.get("classification"), "of mangrove was lost in 2020")

Map.addLayer(gain.selfMask(), {"palette": "green"}, "Gains")
Map.addLayer(loss.selfMask(), {"palette": "red"}, "Loss")

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

# Add Earth Engine dataset image = ee.Image("USGS/SRTMGL1_003") # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # Chapter: A3.3 Mangroves II - Change Mapping # Checkpoint: A33a # Authors: Celio de Sousa, David Lagomasino, and Lola Fatoyinbo # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # STEP 1 - ADD THE MAPS areaOfstudy = ee.FeatureCollection("projects/gee-book/assets/A3-3/Border5km") mangrove2000 = ee.Image("projects/gee-book/assets/A3-3/MangroveGuinea2000_v2") mangrove2020 = ee.Image("projects/gee-book/assets/A3-3/MangroveGuinea2020_v2") Map.setCenter(-13.6007, 9.6295, 10) # Sets the map center to Conakry, Guinea Map.addLayer(areaOfstudy, {}, "Area of Study") Map.addLayer(mangrove2000, {"palette": "#16a596"}, "Mangrove Extent 2000") Map.addLayer(mangrove2020, {"palette": "#9ad3bc"}, "Mangrove Extent 2020") # STEP 2 - MAP TO MAP CHANGE mang2020 = mangrove2020.unmask(0) mang2000 = mangrove2000.unmask(0) change = mang2020.subtract(mang2000).clip(areaOfstudy) paletteCHANGE = [ "red", # Loss/conversion "white", # No Change "green", # Gain/Expansion ] Map.addLayer( change, {"min": -1, "max": 1, "palette": paletteCHANGE}, "Changes 2000-2020" ) # Calculate the area of each pixel gain = change.eq(1) loss = change.eq(-1) gainArea = gain.multiply(ee.Image.pixelArea().divide(1000000)) lossArea = loss.multiply(ee.Image.pixelArea().divide(1000000)) # Sum all the areas statsgain = gainArea.reduceRegion( {"reducer": ee.Reducer.sum(), "scale": 30, "maxPixels": 1e14} ) statsloss = lossArea.reduceRegion( {"reducer": ee.Reducer.sum(), "scale": 30, "maxPixels": 1e14} ) print(statsgain.get("classification"), "km² of new mangroves in 2020") print(statsloss.get("classification"), "of mangrove was lost in 2020") Map.addLayer(gain.selfMask(), {"palette": "green"}, "Gains") Map.addLayer(loss.selfMask(), {"palette": "red"}, "Loss") # ----------------------------------------------------------------------- # CHECKPOINT # -----------------------------------------------------------------------

Display the interactive map¶

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Map

Map