Extracts a stratified random sample of points from an image. Extracts the specified number of samples for each distinct value discovered within the 'classBand'. Returns a FeatureCollection of 1 Feature per extracted point, with each feature having 1 property per band in the input image. If there are less than the specified number of samples available for a given class value, then all of the points for that class will be included. Requires that the classBand contain integer values.
| Usage | Returns | Image.stratifiedSample(numPoints, classBand, region, scale, projection, seed, classValues, classPoints, dropNulls, tileScale, geometries) | FeatureCollection |
| Argument | Type | Details | this: image | Image | The image to sample. |
numPoints | Integer | The default number of points to sample in each class. Can be overridden for specific classes using the 'classValues' and 'classPoints' properties. |
classBand | String, default: null | The name of the band containing the classes to use for stratification. If unspecified, the first band of the input image is used. |
region | Geometry, default: null | The region to sample from. If unspecified, the input image's whole footprint is used. |
scale | Float, default: null | A nominal scale in meters of the projection to sample in. Defaults to the scale of the first band of the input image. |
projection | Projection, default: null | The projection in which to sample. If unspecified, the projection of the input image's first band is used. If specified in addition to scale, rescaled to the specified scale. |
seed | Integer, default: 0 | A randomization seed to use for subsampling. |
classValues | List, default: null | A list of class values for which to override the numPoints parameter. Must be the same size as classPoints or null. |
classPoints | List, default: null | A list of the per-class maximum number of pixels to sample for each class in the classValues list. Must be the same size as classValues or null. |
dropNulls | Boolean, default: true | Skip pixels in which any band is masked. |
tileScale | Float, default: 1 | A 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. |
geometries | Boolean, default: false | If true, the results will include a geometry per sampled pixel. Otherwise, geometries will be omitted (saving memory). |