ee.Geometry.MultiPolygon.centroid

  • Returns a point representing the center of the highest-dimension components within a geometry, ignoring lower dimensions.

  • Accepts optional maxError and proj arguments for error tolerance during reprojection and specifying the output projection, respectively.

  • The default projection for the returned centroid is EPSG:4326 if proj is not specified.

  • Can be applied to MultiPolygon objects to calculate their center point.

 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.

UsageReturns
MultiPolygon.centroid(maxError, proj)Geometry
ArgumentTypeDetails
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 EPSG:4326.

Examples

Code Editor (JavaScript)

// Define a MultiPolygon object.
var multiPolygon = ee.Geometry.MultiPolygon(
    [[[[-122.092, 37.424],
       [-122.086, 37.418],
       [-122.079, 37.425],
       [-122.085, 37.423]]],
     [[[-122.081, 37.417],
       [-122.086, 37.421],
       [-122.089, 37.416]]]]);

// Apply the centroid method to the MultiPolygon object.
var multiPolygonCentroid = multiPolygon.centroid({'maxError': 1});

// Print the result to the console.
print('multiPolygon.centroid(...) =', multiPolygonCentroid);

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

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 MultiPolygon object.
multipolygon = ee.Geometry.MultiPolygon([
    [[
        [-122.092, 37.424],
        [-122.086, 37.418],
        [-122.079, 37.425],
        [-122.085, 37.423],
    ]],
    [[[-122.081, 37.417], [-122.086, 37.421], [-122.089, 37.416]]],
])

# Apply the centroid method to the MultiPolygon object.
multipolygon_centroid = multipolygon.centroid(maxError=1)

# Print the result.
display('multipolygon.centroid(...) =', multipolygon_centroid)

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