earthengine-api/javascript/examples/FeatureCollection/FromPolygons.js

// From polygons
// #section FeatureCollection:1
//
// Create and render a feature collection from polygons.

var fc = new ee.FeatureCollection([
    ee.Feature(
        ee.Feature.Polygon(
            [[-109.05, 41], [-109.05, 37], [-102.05, 37], [-102.05, 41]]),
        {name: 'Colorado', fill: 1}),
    ee.Feature(
        ee.Feature.Polygon(
            [[-114.05, 37.0], [-109.05, 37.0], [-109.05, 41.0],
            [-111.05, 41.0], [-111.05, 42.0], [-114.05, 42.0]]),
        {name: 'Utah', fill: 2})
    ]);

// Fill, then outline the polygons into a blank image.
var image1 = ee.Image(0).mask(0).toByte();
var image2 = image1.paint(fc, 'fill');  // Get color from property named 'fill'
var image3 = image2.paint(fc, 3, 5);    // Outline using color 3, width 5.

addToMap(image3, {
    palette: '000000,FF0000,00FF00,0000FF',
    max: 3,
    opacity: 0.5
});

centerMap(-107, 41, 6);