Google Earth Engine: Labeling polygons according to their attributes

Question

I went through different websites and GEE Guides to find a way to label polygons. But, I could not find a solution for it. Is there anyone who knows how to label polygons based on their attribute data (as in ArcGIS or QGIS)?

Answer 1

There is a package made by Gennadii Donchyts that can do something like that.

var text = require('users/gena/packages:text')

var geometry = /* color: #d63000 */ee.FeatureCollection(
        [ee.Feature(
            ee.Geometry.Polygon(
                [[[-67.61062024461603, -24.643926337087994],
                  [-68.57741711961603, -27.71942562544417],
                  [-64.35866711961603, -28.34007192235468],
                  [-63.12819836961603, -24.96305728059903]]]),
            {
              "system:index": "0",
              "name": "one"
            }),
        ee.Feature(
            ee.Geometry.Polygon(
                [[[-70.24733899461603, -39.39961661613476],
                  [-71.82937024461603, -42.97001338016304],
                  [-65.85280774461603, -43.35466563336871],
                  [-64.44655774461603, -39.94082924349792]]]),
            {
              "system:index": "1",
              "name": "two"
            }),
        ee.Feature(
            ee.Geometry.Polygon(
                [[[-57.94265149461603, -30.33201882072655],
                  [-58.90944836961603, -34.195360416696275],
                  [-54.33913586961603, -34.99121789610241],
                  [-52.22976086961603, -30.937007567008546]]]),
            {
              "system:index": "2",
              "name": "three"
            })]);

Map.addLayer(geometry)

// scale text font relative to the current map scale
var scale = Map.getScale() * 1

var labels = geometry.map(function(feat) {
  feat = ee.Feature(feat)
  var name = ee.String(feat.get("name"))
  var centroid = feat.geometry().centroid()
  var t = text.draw(name, centroid, scale, {
    fontSize:18, 
    textColor:'red',
    outlineWidth: 1,
    outlineColor: 'red'
  })
  return t
})

labels = ee.ImageCollection(labels)
Map.addLayer(labels)

link

Answer 2

Make an ee.Feature of the polygon, for example:

var geometry = ee.Geometry.Polygon(
        [[[-89.91067474237019, 21.22910017997246],
          [-89.90651195397908, 21.221619408800706],
          [-89.88110607019001, 21.230180259976443],
          [-89.88561218133503, 21.238860615702055]]]);
var labels = ee.Dictionary({label: 1, someOtherlabel: 'someText', area: geometry.area()})
var feature = ee.Feature(geometry, labels);
print(feature)