ee.Feature.convexHull

Returns the feature, with the geometry replaced by the convex hull of the original geometry. The convex hull of a single point is the point itself, the convex hull of collinear points is a line, and the convex hull of everything else is a polygon. Note that a degenerate polygon with all vertices on the same line will result in a line segment.
UsageReturns
Feature.convexHull(maxError, proj)Feature
ArgumentTypeDetails
this: featureElementThe feature containing the geometry whole hull is being calculated.
maxErrorErrorMargin, default: nullThe maximum amount of error tolerated when performing any necessary reprojection.
projProjection, default: nullThe projection in which to perform the operation. If not specified, the operation will be performed in a spherical coordinate system, and linear distances will be in meters on the sphere.