ee.Geometry.MultiLineString.convexHull

  • convexHull() returns the smallest convex Geometry that contains all the points in the input Geometry.

  • The returned Geometry type can be a point, a line, or a polygon depending on the input Geometry.

  • This method accepts optional maxError and proj parameters for reprojection purposes.

  • Degenerate polygons, where all vertices lie on the same line, will result in a line segment output.

 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
MultiLineString.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 MultiLineString object.
var multiLineString = ee.Geometry.MultiLineString(
   [[[-122.088, 37.418], [-122.086, 37.422], [-122.082, 37.418]],
    [[-122.087, 37.416], [-122.083, 37.416], [-122.082, 37.419]]]);

// Apply the convexHull method to the MultiLineString object.
var multiLineStringConvexHull = multiLineString.convexHull({'maxError': 1});

// Print the result to the console.
print('multiLineString.convexHull(...) =', multiLineStringConvexHull);

// Display relevant geometries on the map.
Map.setCenter(-122.085, 37.422, 15);
Map.addLayer(multiLineString,
             {'color': 'black'},
             'Geometry [black]: multiLineString');
Map.addLayer(multiLineStringConvexHull,
             {'color': 'red'},
             'Result [red]: multiLineString.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 MultiLineString object.
multilinestring = ee.Geometry.MultiLineString([
    [[-122.088, 37.418], [-122.086, 37.422], [-122.082, 37.418]],
    [[-122.087, 37.416], [-122.083, 37.416], [-122.082, 37.419]],
])

# Apply the convexHull method to the MultiLineString object.
multilinestring_convex_hull = multilinestring.convexHull(maxError=1)

# Print the result.
display('multilinestring.convexHull(...) =', multilinestring_convex_hull)

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