ee.Geometry.Polygon.convexHull

  • Returns the smallest convex Polygon that encloses the given geometry.

  • Accepts an optional maxError for reprojection and an optional proj for the projection to use.

  • The convex hull of a point is the point itself, collinear points result in a line, and other geometries result in a Polygon.

  • May return a degenerate polygon (line segment) if all vertices lie on the same line.

 Returns the convex hull of the given 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
Polygon.convexHull(maxError, proj)Geometry
ArgumentTypeDetails
this: geometryGeometryCalculates the convex hull of this geometry.
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.

Examples

Code Editor (JavaScript)

// Define a Polygon object.
var polygon = ee.Geometry.Polygon(
    [[[-122.092, 37.424],
      [-122.086, 37.418],
      [-122.079, 37.425],
      [-122.085, 37.423]]]);

// Apply the convexHull method to the Polygon object.
var polygonConvexHull = polygon.convexHull({'maxError': 1});

// Print the result to the console.
print('polygon.convexHull(...) =', polygonConvexHull);

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

Python setup

See the Python Environment page for information on the Python API and using geemap for interactive development.

import ee
import geemap.core as geemap

Colab (Python)

# Define a Polygon object.
polygon = ee.Geometry.Polygon([[
    [-122.092, 37.424],
    [-122.086, 37.418],
    [-122.079, 37.425],
    [-122.085, 37.423],
]])

# Apply the convexHull method to the Polygon object.
polygon_convex_hull = polygon.convexHull(maxError=1)

# Print the result.
display('polygon.convexHull(...) =', polygon_convex_hull)

# Display relevant geometries on the map.
m = geemap.Map()
m.set_center(-122.085, 37.422, 15)
m.add_layer(polygon, {'color': 'black'}, 'Geometry [black]: polygon')
m.add_layer(
    polygon_convex_hull, {'color': 'red'}, 'Result [red]: polygon.convexHull'
)
m