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ee.Terrain.aspect

  • This function calculates aspect in degrees from a terrain Digital Elevation Model (DEM).

  • Missing values will occur around the edges of an image because the local gradient is computed using 4-connected neighbors.

  • The functionee.Terrain.aspect(input) takes an elevation image as input and returns an Image.

  • The returned aspect units are in degrees, where 0 is North, 90 is East, 180 is South, and 270 is West.

 Calculates aspect in degrees from a terrain DEM.

The local gradient is computed using the 4-connected neighbors of each pixel, so missing values will occur around the edges of an image.

UsageReturns
ee.Terrain.aspect(input)Image
ArgumentTypeDetails
inputImageAn elevation image, in meters.

Examples

Code Editor (JavaScript)

// A digital elevation model.vardem=ee.Image('NASA/NASADEM_HGT/001').select('elevation');// Calculate slope. Units are degrees, range is [0,90).varslope=ee.Terrain.slope(dem);// Calculate aspect. Units are degrees where 0=N, 90=E, 180=S, 270=W.varaspect=ee.Terrain.aspect(dem);// Display slope and aspect layers on the map.Map.setCenter(-123.457,47.815,11);Map.addLayer(slope,{min:0,max:89.99},'Slope');Map.addLayer(aspect,{min:0,max:359.99},'Aspect');// Use the ee.Terrain.products function to calculate slope, aspect, and// hillshade simultaneously. The output bands are appended to the input image.// Hillshade is calculated based on illumination azimuth=270, elevation=45.varterrain=ee.Terrain.products(dem);print('ee.Terrain.products bands',terrain.bandNames());Map.addLayer(terrain.select('hillshade'),{min:0,max:255},'Hillshade');;

Python setup

See the Python Environment page for information on the Python API and usinggeemap for interactive development.

importeeimportgeemap.coreasgeemap

Colab (Python)

# A digital elevation model.dem=ee.Image('NASA/NASADEM_HGT/001').select('elevation')# Calculate slope. Units are degrees, range is [0,90).slope=ee.Terrain.slope(dem)# Calculate aspect. Units are degrees where 0=N, 90=E, 180=S, 270=W.aspect=ee.Terrain.aspect(dem)# Display slope and aspect layers on the map.m=geemap.Map()m.set_center(-123.457,47.815,11)m.add_layer(slope,{'min':0,'max':89.99},'Slope')m.add_layer(aspect,{'min':0,'max':359.99},'Aspect')# Use the ee.Terrain.products function to calculate slope, aspect, and# hillshade simultaneously. The output bands are appended to the input image.# Hillshade is calculated based on illumination azimuth=270, elevation=45.terrain=ee.Terrain.products(dem)display('ee.Terrain.products bands',terrain.bandNames())m.add_layer(terrain.select('hillshade'),{'min':0,'max':255},'Hillshade')m

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Last updated 2023-10-06 UTC.