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ee.Geometry.Polygon.union
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Returns the union of the two geometries.
| Usage | Returns | Polygon.union(right, maxError, proj) | Geometry |
| Argument | Type | Details | this: left | Geometry | The geometry used as the left operand of the operation. |
right | Geometry | The geometry used as the right operand of the operation. |
maxError | ErrorMargin, default: null | The maximum amount of error tolerated when performing any necessary reprojection. |
proj | Projection, default: null | The 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 Polygon object.
var polygon = ee.Geometry.Polygon(
[[[-122.092, 37.424],
[-122.086, 37.418],
[-122.079, 37.425],
[-122.085, 37.423]]]);
// Define other inputs.
var inputGeom = ee.Geometry.BBox(-122.085, 37.415, -122.075, 37.425);
// Apply the union method to the Polygon object.
var polygonUnion = polygon.union({'right': inputGeom, 'maxError': 1});
// Print the result to the console.
print('polygon.union(...) =', polygonUnion);
// Display relevant geometries on the map.
Map.setCenter(-122.085, 37.422, 15);
Map.addLayer(polygon,
{'color': 'black'},
'Geometry [black]: polygon');
Map.addLayer(inputGeom,
{'color': 'blue'},
'Parameter [blue]: inputGeom');
Map.addLayer(polygonUnion,
{'color': 'red'},
'Result [red]: polygon.union');
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],
]])
# Define other inputs.
input_geom = ee.Geometry.BBox(-122.085, 37.415, -122.075, 37.425)
# Apply the union method to the Polygon object.
polygon_union = polygon.union(right=input_geom, maxError=1)
# Print the result.
display('polygon.union(...) =', polygon_union)
# 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(input_geom, {'color': 'blue'}, 'Parameter [blue]: input_geom')
m.add_layer(polygon_union, {'color': 'red'}, 'Result [red]: polygon.union')
m
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Last updated 2023-10-06 UTC.
[null,null,["Last updated 2023-10-06 UTC."],[[["\u003cp\u003e\u003ccode\u003eunion()\u003c/code\u003e returns a Geometry representing the combined area of two input geometries.\u003c/p\u003e\n"],["\u003cp\u003eThe operation can be performed using a specified projection or a spherical coordinate system with linear distances in meters.\u003c/p\u003e\n"],["\u003cp\u003eAn optional \u003ccode\u003emaxError\u003c/code\u003e parameter controls the tolerance for reprojection errors.\u003c/p\u003e\n"],["\u003cp\u003eIt takes two geometries as inputs: \u003ccode\u003eleft\u003c/code\u003e (the calling geometry) and \u003ccode\u003eright\u003c/code\u003e.\u003c/p\u003e\n"]]],["The `union` method combines two geometries, a `left` and a `right`, into a single geometry representing their union. It accepts optional parameters `maxError`, defining the error tolerance during reprojection, and `proj`, specifying the projection for the operation. If `proj` is not set, operations use a spherical coordinate system. Example usage shows defining a Polygon and a BBox as `inputGeom`, then uniting them using `polygon.union()` method and visualize results.\n"],null,["# ee.Geometry.Polygon.union\n\nReturns the union of the two geometries.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|-------------------------------------------------|----------|\n| Polygon.union`(right, `*maxError* `, `*proj*`)` | Geometry |\n\n| Argument | Type | Details |\n|--------------|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| this: `left` | Geometry | The geometry used as the left operand of the operation. |\n| `right` | Geometry | The geometry used as the right operand of the operation. |\n| `maxError` | ErrorMargin, default: null | The maximum amount of error tolerated when performing any necessary reprojection. |\n| `proj` | Projection, default: null | The 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. |\n\nExamples\n--------\n\n### Code Editor (JavaScript)\n\n```javascript\n// Define a Polygon object.\nvar polygon = ee.Geometry.Polygon(\n [[[-122.092, 37.424],\n [-122.086, 37.418],\n [-122.079, 37.425],\n [-122.085, 37.423]]]);\n\n// Define other inputs.\nvar inputGeom = ee.Geometry.BBox(-122.085, 37.415, -122.075, 37.425);\n\n// Apply the union method to the Polygon object.\nvar polygonUnion = polygon.union({'right': inputGeom, 'maxError': 1});\n\n// Print the result to the console.\nprint('polygon.union(...) =', polygonUnion);\n\n// Display relevant geometries on the map.\nMap.setCenter(-122.085, 37.422, 15);\nMap.addLayer(polygon,\n {'color': 'black'},\n 'Geometry [black]: polygon');\nMap.addLayer(inputGeom,\n {'color': 'blue'},\n 'Parameter [blue]: inputGeom');\nMap.addLayer(polygonUnion,\n {'color': 'red'},\n 'Result [red]: polygon.union');\n```\nPython setup\n\nSee the [Python Environment](/earth-engine/guides/python_install) page for information on the Python API and using\n`geemap` for interactive development. \n\n```python\nimport ee\nimport geemap.core as geemap\n```\n\n### Colab (Python)\n\n```python\n# Define a Polygon object.\npolygon = ee.Geometry.Polygon([[\n [-122.092, 37.424],\n [-122.086, 37.418],\n [-122.079, 37.425],\n [-122.085, 37.423],\n]])\n\n# Define other inputs.\ninput_geom = ee.Geometry.BBox(-122.085, 37.415, -122.075, 37.425)\n\n# Apply the union method to the Polygon object.\npolygon_union = polygon.union(right=input_geom, maxError=1)\n\n# Print the result.\ndisplay('polygon.union(...) =', polygon_union)\n\n# Display relevant geometries on the map.\nm = geemap.Map()\nm.set_center(-122.085, 37.422, 15)\nm.add_layer(polygon, {'color': 'black'}, 'Geometry [black]: polygon')\nm.add_layer(input_geom, {'color': 'blue'}, 'Parameter [blue]: input_geom')\nm.add_layer(polygon_union, {'color': 'red'}, 'Result [red]: polygon.union')\nm\n```"]]