Returns a point at the center of the highest-dimension components of the geometry. Lower-dimensional components are ignored, so the centroid of a geometry containing two polygons, three lines and a point is equivalent to the centroid of a geometry containing just the two polygons.
BBox.centroid(maxError, proj)Geometry
this: geometryGeometryCalculates the centroid of this geometry.
maxErrorErrorMargin, default: nullThe maximum amount of error tolerated when performing any necessary reprojection.
projProjection, default: nullIf specified, the result will be in this projection. Otherwise it will be in WGS84.


Code Editor (JavaScript)

// Define a BBox object.
var bBox = ee.Geometry.BBox(-122.09, 37.42, -122.08, 37.43);

// Apply the centroid method to the BBox object.
var bBoxCentroid = bBox.centroid({'maxError': 1});

// Print the result to the console.
print('bBox.centroid(...) =', bBoxCentroid);

// Display relevant geometries on the map.
Map.setCenter(-122.085, 37.422, 15);
             {'color': 'black'},
             'Geometry [black]: bBox');
             {'color': 'red'},
             'Result [red]: bBox.centroid');