Announcement: All noncommercial projects registered to use Earth Engine beforeApril 15, 2025 mustverify noncommercial eligibility to maintain access. If you have not verified by September 26, 2025, your access may be on hold.

ee.FeatureCollection.merge

  • FeatureCollection.merge() combines two collections into one, including all elements from both.

  • Elements from the first collection have IDs prefixed with "1*" and the second with "2*".

  • For merging many collections, using FeatureCollection.flatten() is recommended over repeated merging for better performance.

 Merges two collections into one. The result has all the elements that were in either collection.

Elements from the first collection will have IDs prefixed with "1" and elements from the second collection will have IDs prefixed with "2".

Note: If many collections need to be merged, consider placing them all in a collection and using FeatureCollection.flatten() instead. Repeated use of FeatureCollection.merge() will result in increasingly long element IDs and reduced performance.
UsageReturns
FeatureCollection.merge(collection2)FeatureCollection
ArgumentTypeDetails
this:collection1FeatureCollectionThe first collection to merge.
collection2FeatureCollectionThe second collection to merge.

Examples

Code Editor (JavaScript)

// FeatureCollection of points representing forest cover.varfcForest=ee.FeatureCollection([ee.Feature(ee.Geometry.Point([-122.248,37.238]),{'id':0,'cover_class':'forest'}),ee.Feature(ee.Geometry.Point([-122.204,37.222]),{'id':1,'cover_class':'forest'}),ee.Feature(ee.Geometry.Point([-122.110,37.199]),{'id':2,'cover_class':'forest'})]);// FeatureCollection of points representing urban cover.varfcUrban=ee.FeatureCollection([ee.Feature(ee.Geometry.Point([-121.953,37.372]),{'id':0,'cover_class':'urban'}),ee.Feature(ee.Geometry.Point([-121.861,37.308]),{'id':1,'cover_class':'urban'}),ee.Feature(ee.Geometry.Point([-121.984,37.372]),{'id':2,'cover_class':'urban'})]);// Merge the two FeatureCollections into one.varfcMerged=fcForest.merge(fcUrban);// Display FeatureCollections on the map.Map.setCenter(-122.034,37.296,11);Map.addLayer(fcForest,{color:'green'},'Forest points');Map.addLayer(fcUrban,{color:'grey'},'Urban points');Map.addLayer(fcMerged,{color:'yellow'},'Protected areas merged');

Python setup

See the Python Environment page for information on the Python API and usinggeemap for interactive development.

importeeimportgeemap.coreasgeemap

Colab (Python)

# FeatureCollection of points representing forest cover.fc_forest=ee.FeatureCollection([ee.Feature(ee.Geometry.Point([-122.248,37.238]),{'id':0,'cover_class':'forest','id':0,'cover_class':'forest',},),ee.Feature(ee.Geometry.Point([-122.204,37.222]),{'id':1,'cover_class':'forest','id':1,'cover_class':'forest',},),ee.Feature(ee.Geometry.Point([-122.110,37.199]),{'id':2,'cover_class':'forest','id':2,'cover_class':'forest',},),])# FeatureCollection of points representing urban cover.fc_urban=ee.FeatureCollection([ee.Feature(ee.Geometry.Point([-121.953,37.372]),{'id':0,'cover_class':'urban','id':0,'cover_class':'urban'},),ee.Feature(ee.Geometry.Point([-121.861,37.308]),{'id':1,'cover_class':'urban','id':1,'cover_class':'urban'},),ee.Feature(ee.Geometry.Point([-121.984,37.372]),{'id':2,'cover_class':'urban','id':2,'cover_class':'urban'},),])# Merge the two FeatureCollections into one.fc_merged=fc_forest.merge(fc_urban)# Display FeatureCollections on the map.m=geemap.Map()m.set_center(-122.034,37.296,11)m.add_layer(fc_forest,{'color':'green'},'Forest points')m.add_layer(fc_urban,{'color':'grey'},'Urban points')m.add_layer(fc_merged,{'color':'yellow'},'Protected areas merged')m

Except as otherwise noted, the content of this page is licensed under theCreative Commons Attribution 4.0 License, and code samples are licensed under theApache 2.0 License. For details, see theGoogle Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.

Last updated 2023-10-06 UTC.