[GIS] Google Earth Engine: Extract values from FeatureCollection as list

extractgoogle-earth-enginejavascriptlist

I'm trying to extract values from a FeatureCollection as a list. Here's some example code that I'm using in Earth Engine's code editor:

var viirs = 
    ee.Image('NOAA/VIIRS/DNB/MONTHLY_V1/VCMCFG/20120401').select('avg_rad');

var maineCounties = 
    ee.FeatureCollection('ft:1S4EB6319wWW2sWQDPhDvmSBIVrD3iEmCLYB7nMM'). 
    filter(ee.Filter.eq('StateName', 'Maine'));

var maineMeansFeatures = viirs.reduceRegions({
  collection: maineCounties,
  reducer: ee.Reducer.mean(),
  scale: 30
});

The "maineMeansFeatures" FeatureCollection has a column called "mean" — I trying to extract the values in "mean" as a list (so, here, it'd be a list of 16 values — one for each feature).

Any ideas on how to do this? (Note: I'm very new to javascript so I'm not that familiar with FeatureCollections).

Best Answer

Take a look at ee.FeatureCollection.aggregate_array:

Aggregates over a given property of the objects in a collection, calculating a list of all the values of the selected property.

So

maineMeansFeatures.aggregate_array("mean")

should bring you an array of "means".

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