ee.Geometry.MultiPolygon.dissolve
Returns the union of the geometry. This leaves single geometries untouched, and unions multi geometries.
Usage | Returns | MultiPolygon.dissolve(maxError, proj) | Geometry |
Argument | Type | Details | this: geometry | Geometry | The geometry to union. |
maxError | ErrorMargin, default: null | The maximum amount of error tolerated when performing any necessary reprojection. |
proj | Projection, default: null | If 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 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 dissolve method to the MultiPolygon object.
var multiPolygonDissolve = multiPolygon.dissolve({'maxError': 1});
// Print the result to the console.
print('multiPolygon.dissolve(...) =', multiPolygonDissolve);
// Display relevant geometries on the map.
Map.setCenter(-122.085, 37.422, 15);
Map.addLayer(multiPolygon,
{'color': 'black'},
'Geometry [black]: multiPolygon');
Map.addLayer(multiPolygonDissolve,
{'color': 'red'},
'Result [red]: multiPolygon.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 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 dissolve method to the MultiPolygon object.
multipolygon_dissolve = multipolygon.dissolve(maxError=1)
# Print the result.
display('multipolygon.dissolve(...) =', multipolygon_dissolve)
# 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_dissolve,
{'color': 'red'},
'Result [red]: multipolygon.dissolve',
)
m
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Last updated 2023-10-06 UTC.
[null,null,["Last updated 2023-10-06 UTC."],[[["The `dissolve()` method returns the union of the geometries within a MultiPolygon, effectively merging them into a single, unified geometry."],["It accepts optional parameters like `maxError` to control the tolerance for reprojection errors and `proj` to specify the projection for the union operation."],["Single geometries remain unaffected by this operation as they are already in their simplest form."],["This function is valuable for simplifying complex MultiPolygons by dissolving internal boundaries and creating a contiguous shape."],["Examples in JavaScript and Python demonstrate the usage of the `dissolve()` method and its impact on a sample MultiPolygon."]]],[]]