ee.Geometry.Polygon.dissolve

  • Returns a Geometry representing the union of the input geometry's components.

  • Primarily used to union the parts of a MultiGeometry, leaving single geometries unchanged.

  • Can be performed in a specified projection using the proj argument or spherically if left unspecified.

  • Accepts an optional maxError argument to control error tolerance during reprojection.

 Returns the union of the geometry. This leaves single geometries untouched, and unions multi geometries.

UsageReturns
Polygon.dissolve(maxError, proj)Geometry
ArgumentTypeDetails
this: geometryGeometryThe geometry to union.
maxErrorErrorMargin, default: nullThe maximum amount of error tolerated when performing any necessary reprojection.
projProjection, default: nullIf specified, the union will be performed in this projection. Otherwise it will be performed in a spherical coordinate system.

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 dissolve method to the Polygon object.
var polygonDissolve = polygon.dissolve({'maxError': 1});

// Print the result to the console.
print('polygon.dissolve(...) =', polygonDissolve);

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

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 dissolve method to the Polygon object.
polygon_dissolve = polygon.dissolve(maxError=1)

# Print the result.
display('polygon.dissolve(...) =', polygon_dissolve)

# 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_dissolve, {'color': 'red'}, 'Result [red]: polygon.dissolve'
)
m