ee.Geometry.difference

  • difference() returns a Geometry representing the portion of the first geometry that does not intersect with the second geometry.

  • It accepts a 'right' Geometry to subtract and optional maxError and proj parameters for reprojection control.

  • The operation is performed in spherical coordinates with distances in meters on the sphere unless a projection is specified.

  • This method is useful for creating new geometries by removing overlapping areas between existing ones.

 Returns the result of subtracting the 'right' geometry from the 'left' geometry.

UsageReturns
Geometry.difference(right, maxError, proj)Geometry
ArgumentTypeDetails
this: leftGeometryThe geometry used as the left operand of the operation.
rightGeometryThe geometry used as the right operand of the operation.
maxErrorErrorMargin, default: nullThe maximum amount of error tolerated when performing any necessary reprojection.
projProjection, default: nullThe 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 Geometry object.
var geometry = ee.Geometry({
  'type': 'Polygon',
  'coordinates':
    [[[-122.081, 37.417],
      [-122.086, 37.421],
      [-122.084, 37.418],
      [-122.089, 37.416]]]
});

// Define other inputs.
var inputGeom = ee.Geometry.BBox(-122.085, 37.415, -122.075, 37.425);

// Apply the difference method to the Geometry object.
var geometryDifference = geometry.difference({'right': inputGeom, 'maxError': 1});

// Print the result to the console.
print('geometry.difference(...) =', geometryDifference);

// Display relevant geometries on the map.
Map.setCenter(-122.085, 37.422, 15);
Map.addLayer(geometry,
             {'color': 'black'},
             'Geometry [black]: geometry');
Map.addLayer(inputGeom,
             {'color': 'blue'},
             'Parameter [blue]: inputGeom');
Map.addLayer(geometryDifference,
             {'color': 'red'},
             'Result [red]: geometry.difference');

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 Geometry object.
geometry = ee.Geometry({
    'type': 'Polygon',
    'coordinates': [[
        [-122.081, 37.417],
        [-122.086, 37.421],
        [-122.084, 37.418],
        [-122.089, 37.416],
    ]],
})

# Define other inputs.
input_geom = ee.Geometry.BBox(-122.085, 37.415, -122.075, 37.425)

# Apply the difference method to the Geometry object.
geometry_difference = geometry.difference(right=input_geom, maxError=1)

# Print the result.
display('geometry.difference(...) =', geometry_difference)

# Display relevant geometries on the map.
m = geemap.Map()
m.set_center(-122.085, 37.422, 15)
m.add_layer(geometry, {'color': 'black'}, 'Geometry [black]: geometry')
m.add_layer(input_geom, {'color': 'blue'}, 'Parameter [blue]: input_geom')
m.add_layer(
    geometry_difference, {'color': 'red'}, 'Result [red]: geometry.difference'
)
m