ui.Thumbnail

AI-generated Key Takeaways

• ui.Thumbnail generates a fixed-size thumbnail image asynchronously from an ee.Image.

• The ui.Thumbnail function takes image, params, onClick, and style as optional arguments and returns a ui.Thumbnail object.

• The image argument specifies the ee.Image for the thumbnail, defaulting to an empty image if not provided.

• The params argument allows setting parameters for the thumbnail, as described in ui.Thumbnail.setParams().

• The onClick argument is a callback function executed when the thumbnail is clicked, and style allows applying CSS styles to the thumbnail.

A fixed-size thumbnail image generated asynchronously from an ee.Image.

Usage	Returns
ui.Thumbnail(image, params, onClick, style)	ui.Thumbnail

Argument	Type	Details
image	Image, optional	The ee.Image from which to generate the thumbnail. Defaults to an empty ee.Image.
params	Object, optional	For an explanation of the possible parameters, see ui.Thumbnail.setParams(). Defaults to an empty object.
onClick	Function, optional	A callback fired when the thumbnail is clicked.
style	Object, optional	An object of allowed CSS styles with their values to be set for this label. Defaults to an empty object.

Examples

Code Editor (JavaScript)

// The goal is to create a series of thumbnail images for an elevation dataset
// with different backgrounds. The background layers and image visualization
// are previewed in the Code Editor map before creating the thumbnails.

// Define a black background.
var blackBg = ee.Image.rgb(0, 0, 0)
  .visualize({min: 0, max: 255});
Map.addLayer(blackBg, {}, 'Black background');

// Define a water / land background.
var waterLandBg = ee.Image('NOAA/NGDC/ETOPO1').select('bedrock').gt(0.0)
  .visualize({palette: ['cadetblue', 'lightgray']});
Map.addLayer(waterLandBg, {}, 'Water / land background');

// A map display of a digital elevation model (DEM).
var image = ee.Image('AU/GA/DEM_1SEC/v10/DEM-S').select('elevation')
  .visualize({
     min: -10.0,
     max: 1300.0,
     palette: [
       '3ae237', 'b5e22e', 'd6e21f', 'fff705', 'ffd611', 'ffb613', 'ff8b13',
       'ff6e08', 'ff500d', 'ff0000', 'de0101', 'c21301', '0602ff', '235cb1',
       '307ef3', '269db1', '30c8e2', '32d3ef', '3be285', '3ff38f', '86e26f'
     ],
  });
Map.addLayer(image, {}, 'Elevation');

// Set the center of the map.
var lon = 133.95;
var lat = -24.69;
Map.setCenter(lon, lat, 4);

// Set the basic parameters for the thumbnail.
// Half-width of the thumbnail in degrees in EPSG:3857.
var delta = 22;
// Width and Height of the Thumbail image.
var pixels = 256;

var areaOfInterest = ee.Geometry.Rectangle(
  [lon - delta, lat - delta, lon + delta, lat + delta], null, false);

var parameters = {
  dimensions: [pixels, pixels],
  region: areaOfInterest,
  crs: 'EPSG:3857',
  format: 'png'};

// Create a thumbnail with no background fill.
// Masked pixels will be transparent.
print(ui.Thumbnail({image: image, params: parameters}));

// Use a black background to replace masked image pixels.
var imageWithBlackBg = blackBg.blend(image);
print(ui.Thumbnail({
  image: imageWithBlackBg, params: parameters}));

// Use the water / land background to replace masked image pixels.
var imageWithWaterLandBg = waterLandBg.blend(image);
print(ui.Thumbnail({
  image: imageWithWaterLandBg, params: parameters}));