Extracting centroids from property of polygons

Question

I have been using a function to get the centroid of each polygon (building) in my dataset.

var buildings = ee.FeatureCollection('GOOGLE/Research/open-buildings/v1/polygons')
Map.addLayer(buildings, {color: 'FF0000'}, 'buildings');
// This function creates a new feature from the centroid of the geometry.
var getCentroid = function(feature) {
  var centroid = feature.geometry().centroid();
  return ee.Feature(centroid)
};
// Map the centroid getting function over the features.
var centroids = buildings.map(getCentroid);
// Display the results.
Map.addLayer(centroids, {color: 'FF0000'}, 'centroids');

However, I noticed that one of the properties of each building is 'longitude_latitude' which already includes the coordinates of the centroid.

print(buildings.first())
print(centroids.first())

Is there any way that I can get the centroids as features from that?

For context: I then try to count the centroids with the code:

// ***************************************************************************
// Change to Image
// ***************************************************************************

// add dummy property to use for reduceToImage
var points = ee.FeatureCollection(centroids).map(function(feature){
  return feature.set('dummy',1)
});
Map.addLayer(points, {color: 'FF0000'}, 'points'); //Confirmed same as centroids
print(points.first())

// specify scale in meters to project point Image to
var ptScale = ee.Number(1000);

// convert featureCollection to Image and add geoinformation
var ptImg = points
  .reduceToImage({
    properties: ['dummy'],
   reducer: ee.Reducer.sum(),
}).reproject('epsg:4326',null,ptScale);

// ***************************************************************************
// Count buildings and display
// ***************************************************************************

// specify output scale, in this case 1km
var outScale = ee.Number(1000);
// reduce resolution of Image and reproject from ptScale to outScale 
var countImg = ptImg.reduceResolution(ee.Reducer.mean(),false,60000)
  .reproject('epsg:4326',null,outScale)
  .multiply(outScale.pow(2)).divide(ptScale.pow(2)).round().int();
// display results!   
Map.addLayer(countImg,{min:0,max:3},'Point Counts');

Answer 1

You still have to map a function over the collection so it's only saving you the centroid() call:

var centroids = buildings.map(function(f) { 
    return ee.Feature(f.get("longitude_latitude"), {}) 
})

What are you going to do with the centroids? There might be a way to short-circuit a little of the work.