Demo of Highlighting

// Load an image.
var image = ee.Image('LANDSAT/LC08/C02/T1_TOA/LC08_044034_20140318');

// Define the visualization parameters.
var vizParams = {
  bands: ['B5', 'B4', 'B3'],
  min: 0,
  max: 0.5,
  gamma: [0.95, 1.1, 1]
};

Map.setCenter(-122.128249, 37.361767); 
Map.addLayer(image, vizParams, 'false color composite');

// Load an image.
var image = ee.Image('LANDSAT/LC08/C02/T1_TOA/LC08_044034_20140318');

// Create an NDWI image, define visualization parameters and display.
var ndwi = image.normalizedDifference(['B3', 'B5']);
var ndwiViz = {min: 0.5, max: 1, palette: ['00FFFF', '0000FF']};
Map.addLayer(ndwi, ndwiViz, 'NDWI', false);

// Mask the non-watery parts of the image, where NDWI < 0.4.
var ndwiMasked = ndwi.updateMask(ndwi.gte(0.4));
Map.addLayer(ndwiMasked, ndwiViz, 'NDWI masked');

// Create visualization layers.
var imageRGB = image.visualize({bands: ['B5', 'B4', 'B3'], max: 0.5});
var ndwiRGB = ndwiMasked.visualize({
  min: 0.5,
  max: 1,
  palette: ['00FFFF', '0000FF']
});

// Mosaic the visualization layers
var mosaic = ee.ImageCollection([imageRGB, ndwiRGB]).mosaic();
Map.addLayer(mosaic, {}, 'mosaic');

//Generating Circle
var roi = ee.Geometry.Point([-122.128, 37.361]).buffer(200);
var roiBuffer = roi.buffer({'distance':2000000});

Map.addLayer(roi);

print('roi(...) =', roi);

//Point at Foothill Campus
var point = ee.Geometry.Point(-122.128, 37.361);

var pointBuffer = point.buffer({'distance': 200});

print('point.buffer(...) =', pointBuffer);

// Display the Point
Map.setCenter(-122.128249, 37.361767);
Map.addLayer(point,
  {'color': 'white'},
  'Geometry [white]: point');
Map.addLayer(pointBuffer,
  {'color': 'black'},
  'Result [red]: point.buffer');