ee.Classifier.smileRandomForest

تنشئ هذه الدالة مصنّف "الغابة العشوائية" فارغًا.

الاستخدام	المرتجعات
ee.Classifier.smileRandomForest(numberOfTrees, variablesPerSplit, minLeafPopulation, bagFraction, maxNodes, seed)	المصنِّف

الوسيطة	النوع	التفاصيل
numberOfTrees	عدد صحيح	عدد أشجار القرارات المطلوب إنشاؤها.
variablesPerSplit	عدد صحيح، القيمة التلقائية: null	عدد المتغيّرات لكل تقسيم. في حال عدم تحديدها، يتم استخدام الجذر التربيعي لعدد المتغيرات.
minLeafPopulation	عدد صحيح، القيمة التلقائية: 1	لا تنشئ عُقدًا تحتوي مجموعة التدريب الخاصة بها على هذا العدد من النقاط على الأقل.
bagFraction	العدد العائم، القيمة التلقائية: 0.5	تمثّل هذه السمة جزء الإدخال إلى الحقيبة لكل شجرة.
maxNodes	عدد صحيح، القيمة التلقائية: null	الحد الأقصى لعدد العُقد الطرفية في كل شجرة. إذا لم يتم تحديدها، تكون القيمة التلقائية هي "بلا حدّ".
seed	عدد صحيح، القيمة التلقائية: 0	القيمة الأساسية للتوزيع العشوائي

أمثلة

محرّر الرموز البرمجية (JavaScript)

// A Sentinel-2 surface reflectance image, reflectance bands selected,
// serves as the source for training and prediction in this contrived example.
var img = ee.Image('COPERNICUS/S2_SR/20210109T185751_20210109T185931_T10SEG')
              .select('B.*');

// ESA WorldCover land cover map, used as label source in classifier training.
var lc = ee.Image('ESA/WorldCover/v100/2020');

// Remap the land cover class values to a 0-based sequential series.
var classValues = [10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 100];
var remapValues = ee.List.sequence(0, 10);
var label = 'lc';
lc = lc.remap(classValues, remapValues).rename(label).toByte();

// Add land cover as a band of the reflectance image and sample 100 pixels at
// 10 m scale from each land cover class within a region of interest.
var roi = ee.Geometry.Rectangle(-122.347, 37.743, -122.024, 37.838);
var sample = img.addBands(lc).stratifiedSample({
  numPoints: 100,
  classBand: label,
  region: roi,
  scale: 10,
  geometries: true
});

// Add a random value field to the sample and use it to approximately split 80%
// of the features into a training set and 20% into a validation set.
sample = sample.randomColumn();
var trainingSample = sample.filter('random <= 0.8');
var validationSample = sample.filter('random > 0.8');

// Train a 10-tree random forest classifier from the training sample.
var trainedClassifier = ee.Classifier.smileRandomForest(10).train({
  features: trainingSample,
  classProperty: label,
  inputProperties: img.bandNames()
});

// Get information about the trained classifier.
print('Results of trained classifier', trainedClassifier.explain());

// Get a confusion matrix and overall accuracy for the training sample.
var trainAccuracy = trainedClassifier.confusionMatrix();
print('Training error matrix', trainAccuracy);
print('Training overall accuracy', trainAccuracy.accuracy());

// Get a confusion matrix and overall accuracy for the validation sample.
validationSample = validationSample.classify(trainedClassifier);
var validationAccuracy = validationSample.errorMatrix(label, 'classification');
print('Validation error matrix', validationAccuracy);
print('Validation accuracy', validationAccuracy.accuracy());

// Classify the reflectance image from the trained classifier.
var imgClassified = img.classify(trainedClassifier);

// Add the layers to the map.
var classVis = {
  min: 0,
  max: 10,
  palette: ['006400' ,'ffbb22', 'ffff4c', 'f096ff', 'fa0000', 'b4b4b4',
            'f0f0f0', '0064c8', '0096a0', '00cf75', 'fae6a0']
};
Map.setCenter(-122.184, 37.796, 12);
Map.addLayer(img, {bands: ['B11', 'B8', 'B3'], min: 100, max: 3500}, 'img');
Map.addLayer(lc, classVis, 'lc');
Map.addLayer(imgClassified, classVis, 'Classified');
Map.addLayer(roi, {color: 'white'}, 'ROI', false, 0.5);
Map.addLayer(trainingSample, {color: 'black'}, 'Training sample', false);
Map.addLayer(validationSample, {color: 'white'}, 'Validation sample', false);

إعداد Python

راجِع صفحة بيئة Python للحصول على معلومات حول واجهة برمجة التطبيقات Python واستخدام geemap للتطوير التفاعلي.

import ee
import geemap.core as geemap

Colab (Python)

# A Sentinel-2 surface reflectance image, reflectance bands selected,
# serves as the source for training and prediction in this contrived example.
img = ee.Image(
    'COPERNICUS/S2_SR/20210109T185751_20210109T185931_T10SEG'
).select('B.*')

# ESA WorldCover land cover map, used as label source in classifier training.
lc = ee.Image('ESA/WorldCover/v100/2020')

# Remap the land cover class values to a 0-based sequential series.
class_values = [10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 100]
remap_values = ee.List.sequence(0, 10)
label = 'lc'
lc = lc.remap(class_values, remap_values).rename(label).toByte()

# Add land cover as a band of the reflectance image and sample 100 pixels at
# 10 m scale from each land cover class within a region of interest.
roi = ee.Geometry.Rectangle(-122.347, 37.743, -122.024, 37.838)
sample = img.addBands(lc).stratifiedSample(
    numPoints=100, classBand=label, region=roi, scale=10, geometries=True
)

# Add a random value field to the sample and use it to approximately split 80%
# of the features into a training set and 20% into a validation set.
sample = sample.randomColumn()
training_sample = sample.filter('random <= 0.8')
validation_sample = sample.filter('random > 0.8')

# Train a 10-tree random forest classifier from the training sample.
trained_classifier = ee.Classifier.smileRandomForest(10).train(
    features=training_sample,
    classProperty=label,
    inputProperties=img.bandNames(),
)

# Get information about the trained classifier.
display('Results of trained classifier', trained_classifier.explain())

# Get a confusion matrix and overall accuracy for the training sample.
train_accuracy = trained_classifier.confusionMatrix()
display('Training error matrix', train_accuracy)
display('Training overall accuracy', train_accuracy.accuracy())

# Get a confusion matrix and overall accuracy for the validation sample.
validation_sample = validation_sample.classify(trained_classifier)
validation_accuracy = validation_sample.errorMatrix(label, 'classification')
display('Validation error matrix', validation_accuracy)
display('Validation accuracy', validation_accuracy.accuracy())

# Classify the reflectance image from the trained classifier.
img_classified = img.classify(trained_classifier)

# Add the layers to the map.
class_vis = {
    'min': 0,
    'max': 10,
    'palette': [
        '006400',
        'ffbb22',
        'ffff4c',
        'f096ff',
        'fa0000',
        'b4b4b4',
        'f0f0f0',
        '0064c8',
        '0096a0',
        '00cf75',
        'fae6a0',
    ],
}
m = geemap.Map()
m.set_center(-122.184, 37.796, 12)
m.add_layer(
    img, {'bands': ['B11', 'B8', 'B3'], 'min': 100, 'max': 3500}, 'img'
)
m.add_layer(lc, class_vis, 'lc')
m.add_layer(img_classified, class_vis, 'Classified')
m.add_layer(roi, {'color': 'white'}, 'ROI', False, 0.5)
m.add_layer(training_sample, {'color': 'black'}, 'Training sample', False)
m.add_layer(
    validation_sample, {'color': 'white'}, 'Validation sample', False
)
m