ee.Geometry.convexHull

  • Returns a Geometry representing the smallest convex Polygon that contains all the points in the input Geometry.

  • Accepts an optional maxError parameter for reprojection tolerance and a proj parameter to specify the projection for the operation.

  • If the input is a single point, a line, or collinear points, the function returns the corresponding Geometry (point, line segment, or line, respectively).

  • For all other geometries, the result is a Polygon encompassing all input points, potentially degenerating into a line segment if all vertices are collinear.

 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
Geometry.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 Geometry object.
var geometry = ee.Geometry({
  'type': 'Polygon',
  'coordinates':
    [[[-122.081, 37.417],
      [-122.086, 37.421],
      [-122.084, 37.418],
      [-122.089, 37.416]]]
});

// Apply the convexHull method to the Geometry object.
var geometryConvexHull = geometry.convexHull({'maxError': 1});

// Print the result to the console.
print('geometry.convexHull(...) =', geometryConvexHull);

// Display relevant geometries on the map.
Map.setCenter(-122.085, 37.422, 15);
Map.addLayer(geometry,
             {'color': 'black'},
             'Geometry [black]: geometry');
Map.addLayer(geometryConvexHull,
             {'color': 'red'},
             'Result [red]: geometry.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 Geometry object.
geometry = ee.Geometry({
    'type': 'Polygon',
    'coordinates': [[
        [-122.081, 37.417],
        [-122.086, 37.421],
        [-122.084, 37.418],
        [-122.089, 37.416],
    ]],
})

# Apply the convexHull method to the Geometry object.
geometry_convex_hull = geometry.convexHull(maxError=1)

# Print the result.
display('geometry.convexHull(...) =', geometry_convex_hull)

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