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ee.FeatureCollection.merge

AI-generated Key Takeaways

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 ".

Usage	Returns
`FeatureCollection. merge (collection2)`	FeatureCollection

Argument	Type	Details
this: `collection1`	FeatureCollection	The first collection to merge.
`collection2`	FeatureCollection	The second collection to merge.

Examples

Code Editor (JavaScript)

 // FeatureCollection of points representing forest cover. 
 var 
  
 fcForest 
  
 = 
  
 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. 
 var 
  
 fcUrban 
  
 = 
  
 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. 
 var 
  
 fcMerged 
  
 = 
  
 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 using geemap for interactive development.

 import 
  
 ee 
 import 
  
 geemap.core 
  
 as 
  
 geemap

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