ee.FeatureCollection.classify

Classifies each feature in a collection.

Usage	Returns
`FeatureCollection.classify(classifier, outputName)`	FeatureCollection

Argument	Type	Details
this: `features`	FeatureCollection	The collection of features to classify. Each feature must contain all the properties in the classifier's schema.
`classifier`	Classifier	The classifier to use.
`outputName`	String, default: "classification"	The name of the output property to be added. This argument is ignored if the classifier has more than one output.

Examples

Code Editor (JavaScript)

/**
 * Classifies features in a FeatureCollection and computes an error matrix.
 */

// Combine Landsat and NLCD images using only the bands representing
// predictor variables (spectral reflectance) and target labels (land cover).
var spectral =
    ee.Image('LANDSAT/LC08/C02/T1_L2/LC08_038032_20160820').select('SR_B[1-7]');
var landcover =
    ee.Image('USGS/NLCD_RELEASES/2016_REL/2016').select('landcover');
var sampleSource = spectral.addBands(landcover);

// Sample the combined images to generate a FeatureCollection.
var sample = sampleSource.sample({
  region: spectral.geometry(),  // sample only from within Landsat image extent
  scale: 30,
  numPixels: 2000,
  geometries: true
})
// Add a random value column with uniform distribution for hold-out
// training/validation splitting.
.randomColumn({distribution: 'uniform'});
print('Sample for classifier development', sample);

// Split out ~80% of the sample for training the classifier.
var training = sample.filter('random < 0.8');
print('Training set', training);

// Train a random forest classifier.
var classifier = ee.Classifier.smileRandomForest(10).train({
  features: training,
  classProperty: landcover.bandNames().get(0),
  inputProperties: spectral.bandNames()
});

// Classify the sample.
var predictions = sample.classify(
    {classifier: classifier, outputName: 'predicted_landcover'});
print('Predictions', predictions);

// Split out the validation feature set.
var validation = predictions.filter('random >= 0.8');
print('Validation set', validation);

// Get a list of possible class values to use for error matrix axis labels.
var order = sample.aggregate_array('landcover').distinct().sort();
print('Error matrix axis labels', order);

// Compute an error matrix that compares predicted vs. expected values.
var errorMatrix = validation.errorMatrix({
  actual: landcover.bandNames().get(0),
  predicted: 'predicted_landcover',
  order: order
});
print('Error matrix', errorMatrix);

// Compute accuracy metrics from the error matrix.
print("Overall accuracy", errorMatrix.accuracy());
print("Consumer's accuracy", errorMatrix.consumersAccuracy());
print("Producer's accuracy", errorMatrix.producersAccuracy());
print("Kappa", errorMatrix.kappa());

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)

from pprint import pprint

# Classifies features in a FeatureCollection and computes an error matrix.

# Combine Landsat and NLCD images using only the bands representing
# predictor variables (spectral reflectance) and target labels (land cover).
spectral = ee.Image('LANDSAT/LC08/C02/T1_L2/LC08_038032_20160820').select(
    'SR_B[1-7]')
landcover = ee.Image('USGS/NLCD_RELEASES/2016_REL/2016').select('landcover')
sample_source = spectral.addBands(landcover)

# Sample the combined images to generate a FeatureCollection.
sample = sample_source.sample(**{
    # sample only from within Landsat image extent
    'region': spectral.geometry(),
    'scale': 30,
    'numPixels': 2000,
    'geometries': True
})
# Add a random value column with uniform distribution for hold-out
# training/validation splitting.
sample = sample.randomColumn(**{'distribution': 'uniform'})
print('Sample for classifier development:', sample.getInfo())

# Split out ~80% of the sample for training the classifier.
training = sample.filter('random < 0.8')
print('Training set:', training.getInfo())

# Train a random forest classifier.
classifier = ee.Classifier.smileRandomForest(10).train(**{
    'features': training,
    'classProperty': landcover.bandNames().get(0),
    'inputProperties': spectral.bandNames()
})

# Classify the sample.
predictions = sample.classify(
    **{'classifier': classifier, 'outputName': 'predicted_landcover'})
print('Predictions:', predictions.getInfo())

# Split out the validation feature set.
validation = predictions.filter('random >= 0.8')
print('Validation set:', validation.getInfo())

# Get a list of possible class values to use for error matrix axis labels.
order = sample.aggregate_array('landcover').distinct().sort()
print('Error matrix axis labels:', order.getInfo())

# Compute an error matrix that compares predicted vs. expected values.
error_matrix = validation.errorMatrix(**{
    'actual': landcover.bandNames().get(0),
    'predicted': 'predicted_landcover',
    'order': order
})
print('Error matrix:')
pprint(error_matrix.getInfo())

# Compute accuracy metrics from the error matrix.
print('Overall accuracy:', error_matrix.accuracy().getInfo())
print('Consumer\'s accuracy:')
pprint(error_matrix.consumersAccuracy().getInfo())
print('Producer\'s accuracy:')
pprint(error_matrix.producersAccuracy().getInfo())
print('Kappa:', error_matrix.kappa().getInfo())