Google Earth Engine: set Feature to FeatureCollection, but not a whole Array

Question

I try to add a new Feature to the large Feature Collection, but with a function set() its override the whole list to each feature. But my purpose is to add each value from the array to the corresponding FeatureCollection. Can anybody help me?

    var table = ee.FeatureCollection(ft:.....blablabla);

    **//Create an Array from the property DN in the FeatureCollection:**
        var propert = table.limit(100).aggregate_array('DN');
    *// Values less than 1 will be set to 1, larger than 1== 0:* 
        var limit =  ee.Array(propert).lt(1);
        print(limit);
     //Function, that add the list! of features (limit) to new property (Class) in the FeatureCollection ("table"). 
        var addFeature = function(ar) {
          return ar.set({Class: limit});
     //Map throw the Featurecollection table
        var areaAdded = table.limit(100).map(addArea);
        };

So, if you can see, my code add the whole Array [limit] to each property in the FeatureCollection, not a first Value from the Array to the first property and so on... Could anybody help me? thank you

Answer 1

If you have a smallish number of features, you can convert the feature collection to a list, convert the array to a list, zip() them together, map a function over the lists to set the property. Toy example:

var features = [
  ee.Feature(ee.Geometry.Rectangle(30.01, 59.80, 30.59, 60.15), {name: 'Voronoi'}),
  ee.Feature(ee.Geometry.Point(-73.96, 40.781), {name: 'Thiessen'}),
  ee.Feature(ee.Geometry.Point(6.4806, 50.8012), {name: 'Dirichlet'})
];

var fromList = ee.FeatureCollection(features);

var array = ee.Array([2, 3, 5]);

var lists = fromList.toList(fromList.size()).zip(array.toList());

var features = ee.FeatureCollection(lists.map(function(l) {
  return ee.Feature(ee.List(l).get(0)).set('foo', ee.List(l).get(1));
}));
print(features);