49 lines
1.3 KiB
JavaScript
49 lines
1.3 KiB
JavaScript
// Calculate slope and aspect
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// Calculate statistics
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//Detailed description: https://developers.google.com/earth-engine/tutorial_api_03
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// Load the SRTM image.
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var srtm = ee.Image('CGIAR/SRTM90_V4');
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// Apply an algorithm to an image.
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var slope = ee.Terrain.slope(srtm);
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print(slope)
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// Convert degree in percent
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// Display the result.
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Map.setCenter(12.978717025594149,47.55544193154224,11); // Center on Königsee.
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Map.addLayer(srtm, {min: 0, max :2500}, 'srtm');
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Map.addLayer(slope, {min: 0, max :60}, 'slope');
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//Image math
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// Get the aspect (in degrees).
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var aspect = ee.Terrain.aspect(srtm);
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// Convert to radians, compute the sin of the aspect.
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var sinImage = aspect.divide(180).multiply(Math.PI).sin();
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// Display the result.
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Map.addLayer(sinImage, {min: -1, max: 1}, 'sin');
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// Image statistics
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// Compute the mean elevation in the polygon.
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var stddevDict = srtm.reduceRegion({
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reducer: ee.Reducer.stdDev(),
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geometry: koenigsee,
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scale: 90
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});
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// Print dictionary
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print("dict", stddevDict)
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// Get the mean from the dictionary and print it.
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// In java a dictionary is a collection of different kinds of information.
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// In other languages such as R a dictionary is usally named 'object'.
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var stddev = stddevDict.get('elevation');
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print('stdDev elevation', stddev);
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