gee数据集:ASTER全球数字高程模型（GDEM）v3

var countries = ee.FeatureCollection("FAO/GAUL/2015/level0"),
    GDEM = ee.Image("projects/sat-io/open-datasets/ASTER/GDEM");

var palettes = require('users/samapriya/utils:palettes');


// Add the elevation to the map.  Play with the visualization tools
// to get a better visualization.
Map.addLayer(GDEM, {}, 'elev', false);

// Use the terrain algorithms to compute a hillshade with 8-bit values.
var shade = ee.Terrain.hillshade(GDEM);
Map.addLayer(shade, {}, 'hillshade', false);

// Create an "ocean" variable to be used for cartographic purposes
var ocean = GDEM.lte(0);
Map.addLayer(ocean.mask(ocean), {palette:'000022'}, 'ocean', false);

// Use these visualization parameters, customized by location.
var visParams = {min: 1, max: 3000, palette: palettes.extra.blkred};

// Create a mosaic of the ocean and the elevation data
var visualized = ee.ImageCollection([
  // Mask the elevation to get only land
  GDEM.mask(ocean.not()).visualize(visParams), 
  // Use the ocean mask directly to display ocean.
  ocean.mask(ocean).visualize({palette:'000022'})
]).mosaic();

// Note that the visualization image doesn't require visualization parameters.
Map.addLayer(visualized.clip(countries), {}, 'ASTER GDEM');