ee.Geometry.MultiPolygon.length

  • Calculates the total length of the linear segments within a geometry, excluding any polygonal areas.

  • For MultiPolygons, the total length is the sum of the lengths of all linear components across all polygons.

  • The length can be calculated in meters or in the units of a specified projection.

  • An optional maxError parameter controls the error tolerance during reprojection if a projection is used.

Returns the length of the linear parts of the geometry. Polygonal parts are ignored. The length of multi geometries is the sum of the lengths of their components.

UsageReturns
MultiPolygon.length(maxError, proj)Float
ArgumentTypeDetails
this: geometryGeometryThe input geometry.
maxErrorErrorMargin, default: nullThe maximum amount of error tolerated when performing any necessary reprojection.
projProjection, default: nullIf specified, the result will be in the units of the coordinate system of this projection. Otherwise it will be in meters.

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 length method to the MultiPolygon object.
var multiPolygonLength = multiPolygon.length();

// Print the result to the console.
print('multiPolygon.length(...) =', multiPolygonLength);

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

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 length method to the MultiPolygon object.
multipolygon_length = multipolygon.length()

# Print the result.
display('multipolygon.length(...) =', multipolygon_length)

# 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