ee.Image.sampleRegions

Converts each pixel of an image (at a given scale) that intersects one or more regions to a Feature, returning them as a FeatureCollection. Each output feature will have one property per band of the input image, as well as any specified properties copied from the input feature.

Note that geometries will be snapped to pixel centers.

UsageReturns
Image.sampleRegions(collection, properties, scale, projection, tileScale, geometries)FeatureCollection
ArgumentTypeDetails
this: imageImageThe image to sample.
collectionFeatureCollectionThe regions to sample over.
propertiesList, default: nullThe list of properties to copy from each input feature. Defaults to all non-system properties.
scaleFloat, default: nullA nominal scale in meters of the projection to sample in. If unspecified,the scale of the image's first band is used.
projectionProjection, default: nullThe projection in which to sample. If unspecified, the projection of the image's first band is used. If specified in addition to scale, rescaled to the specified scale.
tileScaleFloat, default: 1A scaling factor used to reduce aggregation tile size; using a larger tileScale (e.g. 2 or 4) may enable computations that run out of memory with the default.
geometriesBoolean, default: falseIf true, the results will include a point geometry per sampled pixel. Otherwise, geometries will be omitted (saving memory).

Examples

Code Editor (JavaScript)

// A Sentinel-2 surface reflectance image.
var img = ee.Image('COPERNICUS/S2_SR/20210109T185751_20210109T185931_T10SEG');
Map.setCenter(-122.503881, 37.765588, 18);
Map.addLayer(img, {bands: ['B11', 'B8', 'B3'], min: 100, max: 4500}, 'img');

// A feature collection with two polygon regions each intersecting 36
// pixels at 10 m scale.
var fcPolygon = ee.FeatureCollection([
  ee.Feature(ee.Geometry.Rectangle(
    -122.50620929, 37.76502806, -122.50552264, 37.76556663), {id: 0}),
  ee.Feature(ee.Geometry.Rectangle(
    -122.50530270, 37.76565568, -122.50460533, 37.76619425), {id: 1})
]);
Map.addLayer(fcPolygon, {color: 'yellow'}, 'fcPolygon');

var fcPolygonSamp = img.sampleRegions({
  collection: fcPolygon,
  scale: 10,
  geometries: true
});
// Note that 7 pixels are missing from the sample. If a pixel contains a masked
// band value it will be excluded from the sample. In this case, the TCI_B band
// is masked for each unsampled pixel.
print('A feature per pixel (at given scale) in each region', fcPolygonSamp);
Map.addLayer(fcPolygonSamp, {color: 'purple'}, 'fcPolygonSamp');

// A feature collection with two points intersecting two different pixels.
// This example is included to show the behavior for point geometries. In
// practice, if the feature collection is all points, ee.Image.reduceRegions
// should be used instead to save memory.
var fcPoint = ee.FeatureCollection([
  ee.Feature(ee.Geometry.Point([-122.50309256, 37.76605006]), {id: 0}),
  ee.Feature(ee.Geometry.Point([-122.50344661, 37.76560903]), {id: 1})
]);
Map.addLayer(fcPoint, {color: 'cyan'}, 'fcPoint');

var fcPointSamp = img.sampleRegions({
  collection: fcPoint,
  scale: 10
});
print('A feature per point', fcPointSamp);