How to reduceresolution of an Image using the most frequent value

Question

Does anyone have an idea how I could aggregate my Image so that in the output the most frequent value is used, as shown on the picture?

this is the same question as aggregate raster using the most frequent value but using the earthengine API

Is this for an export or for rendering directly on a map? If export, just set the pyramiding policy to mode. — Daniel Wiell, Jul 20 '21 at 08:38

Daniel Wiell · Accepted Answer · 2021-07-20T09:15:32.717

0

You control how pixels are aggregated with the pyramidPolicy property in exports. In your case, you want to use mode.

var image = ee.Image('USGS/GFSAD1000_V1')
  .clip(geometry)
Export.image.toAsset({
  image: image, 
  pyramidingPolicy: {'.default': 'mode'}, 
  scale: 100000
})

https://code.earthengine.google.com/cc36b36bc0d8374dcf3483c87252f0eb

Update

When exporting to drive, pyramidingPolicy cannot be specified. Something like this could work:

var scale = 10000
var image = ee.Image('USGS/GFSAD1000_V1')
  .clip(geometry)
var reprojected = image
  .reduceResolution({
    reducer: ee.Reducer.mode(),
    maxPixels: 65536 // Max input pixels for each output pixel
  })
Export.image.toDrive({
  image: reprojected,
  scale: scale
})

https://code.earthengine.google.com/4058242ee0216ab76b9343a675066e7d

edited Jul 20 '21 at 09:15

answered Jul 20 '21 at 08:46

Daniel Wiell

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if I try to export to drive, I get the following error : EEException: Unknown configuration options: {'pyramidingPolicy': 'mean'}. Is there a trick to use it anyway ? – Pierrick Rambaud Jul 20 '21 at 08:50
1

I was editing your answer with the exact same solution. The reproject is not needed – Pierrick Rambaud Jul 20 '21 at 09:14

How to reduceresolution of an Image using the most frequent value

1 Answers1