Calculates slope, aspect, and a simple hillshade from a terrain DEM.
Expects an image containing either a single band of elevation, measured in meters, or if there's more than one band, one named 'elevation'. Adds output bands named 'slope' and 'aspect' measured in degrees plus an unsigned byte output band named 'hillshade' for visualization. All other bands and metadata are copied from the input image. The local gradient is computed using the 4-connected neighbors of each pixel, so missing values will occur around the edges of an image.
| Usage | Returns | ee.Terrain.products(input) | Image |
| Argument | Type | Details | input | Image | An elevation image, in meters. |
Examples
Code Editor (JavaScript)
// A digital elevation model.
var dem = ee.Image('NASA/NASADEM_HGT/001').select('elevation');
// Calculate slope. Units are degrees, range is [0,90).
var slope = ee.Terrain.slope(dem);
// Calculate aspect. Units are degrees where 0=N, 90=E, 180=S, 270=W.
var aspect = 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.
var terrain = 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 using
geemap for interactive development.
import ee
import geemap.core as geemap
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