68 lines
2.2 KiB
JavaScript
68 lines
2.2 KiB
JavaScript
//You are now ready to answer the question at the start of this
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//section - how much forest area was lost in the Republic of the Congo in
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//2012, and how much of that was in protected areas?
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// Load country features from Large Scale International Boundary (LSIB) dataset.
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var countries = ee.FeatureCollection('USDOS/LSIB_SIMPLE/2017');
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// Subset the Congo Republic feature from countries.
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var congo = ee.Feature(
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countries
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.filter(ee.Filter.eq('country_na', 'Rep of the Congo'))
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.first()
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);
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// Subset protected areas to the bounds of the feature of the Republic of the Congo
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// and other criteria. Clip to the intersection with the Republic of the Congo.
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var protectedAreas = ee.FeatureCollection('WCMC/WDPA/current/polygons')
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.filter(ee.Filter.and(
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ee.Filter.bounds(congo.geometry()),
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ee.Filter.neq('IUCN_CAT', 'VI'),
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ee.Filter.neq('STATUS', 'proposed'),
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ee.Filter.lt('STATUS_YR', 2010)
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))
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.map(function(feat){
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return congo.intersection(feat);
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});
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// Get the loss image.
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var gfc2014 = ee.Image('UMD/hansen/global_forest_change_2015');
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var lossIn2012 = gfc2014.select(['lossyear']).eq(12);
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var areaImage = lossIn2012.multiply(ee.Image.pixelArea());
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// Calculate the area of loss pixels in the Republic of the Congo.
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var stats = areaImage.reduceRegion({
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reducer: ee.Reducer.sum(),
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geometry: congo.geometry(),
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scale: 30,
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maxPixels: 1e9
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});
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print(
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'Area lost in the Republic of the Congo:',
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stats.get('lossyear'),
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'square meters'
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);
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// Calculate the area of loss pixels in the protected areas.
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var stats2 = areaImage.reduceRegion({
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reducer: ee.Reducer.sum(),
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geometry: protectedAreas.geometry(),
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scale: 30,
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maxPixels: 2e9
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});
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print(
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'Area lost in protected areas:',
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stats2.get('lossyear'),
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'square meters'
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);
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//The only changes between this script and the one just prior are the
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//addition of the protected area information and changing the script
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//from looking at overall loss to looking at loss in 2012. This required
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//two changes. First, there's a new lossIn2012 image which has a 1 where loss
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//was recorded in 2012, 0 otherwise. Second, because the name of the band is different
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//(lossyear instead of loss) the property name had to change in the print statement.
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