IssueTracker

I need to code a function that has a consistant behaviour whatever the number of bands of the source image. As reported in https://issuetracker.google.com/issues/327605560 the reducers are not. if the source image is a single band image then the output result is using the reducer name if not it's using the band name. I want to make sure it's always using the band name so I did the following:

var ecoregions = ee.FeatureCollection("projects/google/charts_feature_example").select(["label", "value","warm"])
var normClim = ee.ImageCollection('OREGONSTATE/PRISM/Norm91m').toBands()

// reduce the number of bands to one to justify use of the setOutputs method 
normClim = normClim.select(["01_tmean", "02_tmean", "03_tmean", "04_tmean", "05_tmean", "06_tmean", "07_tmean", "08_tmean", "09_tmean", "10_tmean", "11_tmean", "12_tmean"])
var labels = ee.List(['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct', 'nov', 'dec'])
var reducer = ee.Reducer.mean().setOutputs(labels)

// retreive the reduce bands for each feature
var fc = normClim.reduceRegions({
  collection: ecoregions,
  reducer: reducer, 
  scale: 10000
})

print(fc)

and I got the following error:

FeatureCollection (Error) Reducer.setOutputs: Need 1 output names for Reducer.mean.

I initially though it was a parsing error and you were badly interpreting the Computed object so I directly use the raw list and it crashed as well.

var ecoregions = ee.FeatureCollection("projects/google/charts_feature_example").select(["label", "value","warm"])
var normClim = ee.ImageCollection('OREGONSTATE/PRISM/Norm91m').toBands()

normClim = normClim.select(["01_tmean", "02_tmean", "03_tmean", "04_tmean", "05_tmean", "06_tmean", "07_tmean", "08_tmean", "09_tmean", "10_tmean", "11_tmean", "12_tmean"])
var reducer = ee.Reducer.mean().setOutputs(['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct', 'nov', 'dec'])

// retreive the reduce bands for each feature
var fc = normClim.reduceRegions({
  collection: ecoregions,
  reducer: reducer, 
  scale: 10000
})

print(fc)

So I last resort I came back to the example you gave to me when I opened https://issuetracker.google.com/issues/327605560: https://code.earthengine.google.com/4de51d4647db94dca1efff20cc7aacac and all the calls to setOuputs with more than 1 band are broken. Can you rapidly investigate, my LDC pipeline are heavily relying on this.