Page Summary
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Computes the number of non-null inputs.
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The output name is "count".
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No arguments are required for this Reducer.
| Usage | Returns |
|---|---|
ee.Reducer.count()
|
Reducer |
No arguments.
Examples
Code Editor (JavaScript)
print ( ee . List ([]). reduce ( ee . Reducer . count ())); // 0 print ( ee . List ([ 0 ]). reduce ( ee . Reducer . count ())); // 1 print ( ee . List ([ - 1 ]). reduce ( ee . Reducer . count ())); // 1 print ( ee . List ([ 1 , null , 3 ]). reduce ( ee . Reducer . count ())); // 2 print ( ee . List ([ 1 , '' , 3 ]). reduce ( ee . Reducer . count ())); // 3 print ( ee . Array ([ 1 , 0 , 3 ]). reduce ( ee . Reducer . count (), [ 0 ])); // [3] var anArray = ee . Array ([[ 1 , 0 , 3 ], [ 1 , 2 , 3 ]]); print ( anArray . reduce ( ee . Reducer . count (), [ 0 ])); // [[2, 2, 2]] print ( anArray . reduce ( ee . Reducer . count (), [ 1 ])); // [[3], [3]] print ( anArray . reduce ( ee . Reducer . count (), [ 1 , 0 ])); // [[6]] // Use reduceRegion to apply count(). var elev = ee . Image ( 'CGIAR/SRTM90_V4' ); var roi = ee . Geometry . Point ([ - 119.86 , 37.74 ]). buffer ( 5000 ); // Create a mask where elevation is greater than 2000 meters. var highElevMask = elev . gt ( 2000 ); // Update the image with the mask. Pixels = 0 in the mask become null/masked. var maskedElev = elev . updateMask ( highElevMask ); // Run the count reducer. Masked pixels are ignored. var highElevCount = maskedElev . reduceRegion ({ reducer : ee . Reducer . count (), geometry : roi , scale : 90 , maxPixels : 1e9 }); print ( 'Count of pixels > 2000m:' , highElevCount . get ( 'elevation' )); // 20
import ee import geemap.core as geemap
Colab (Python)
display ( ee . List ([]) . reduce ( ee . Reducer . count ())) # 0 display ( ee . List ([ 0 ]) . reduce ( ee . Reducer . count ())) # 1 display ( ee . List ([ - 1 ]) . reduce ( ee . Reducer . count ())) # 1 display ( ee . List ([ 1 , None , 3 ]) . reduce ( ee . Reducer . count ())) # 2 display ( ee . List ([ 1 , '' , 3 ]) . reduce ( ee . Reducer . count ())) # 3 display ( ee . Array ([ 1 , 0 , 3 ]) . reduce ( ee . Reducer . count (), [ 0 ])) # [3] an_array = ee . Array ([[ 1 , 0 , 3 ], [ 1 , 2 , 3 ]]) display ( an_array . reduce ( ee . Reducer . count (), [ 0 ])) # [[2, 2, 2]] display ( an_array . reduce ( ee . Reducer . count (), [ 1 ])) # [[3], [3]] display ( an_array . reduce ( ee . Reducer . count (), [ 1 , 0 ])) # [[6]] # Use reduceRegion to apply count(). elev = ee . Image ( 'CGIAR/SRTM90_V4' ) roi = ee . Geometry . Point ([ - 119.86 , 37.74 ]) . buffer ( 5000 ) # Create a mask where elevation is greater than 2000 meters. high_elev_mask = elev . gt ( 2000 ) # Update the image with the mask. Pixels = 0 in the mask become null/masked. masked_elev = elev . updateMask ( high_elev_mask ) # Run the count reducer. Masked pixels are ignored. high_elev_count = masked_elev . reduceRegion ( reducer = ee . Reducer . count (), geometry = roi , scale = 90 , maxPixels = int ( 1e9 ) ) display ( 'Count of pixels > 2000m:' , high_elev_count . get ( 'elevation' )) # 20
