ee.Geometry.Polygon.buffer

  • The buffer method returns a geometry buffered by a given distance.

  • A positive distance expands the geometry, while a negative distance contracts it.

  • The buffer method can take optional arguments for maximum error and projection.

  • The unit of the distance is meters by default, or the unit of the specified projection.

 Returns the input buffered by a given distance. If the distance is positive, the geometry is expanded, and if the distance is negative, the geometry is contracted.

UsageReturns
Polygon.buffer(distance, maxError, proj)Geometry
ArgumentTypeDetails
this: geometryGeometryThe geometry being buffered.
distanceFloatThe distance of the buffering, which may be negative. If no projection is specified, the unit is meters. Otherwise the unit is in the coordinate system of the projection.
maxErrorErrorMargin, default: nullThe maximum amount of error tolerated when approximating the buffering circle and performing any necessary reprojection. If unspecified, defaults to 1% of the distance.
projProjection, default: nullIf specified, the buffering will be performed in this projection and the distance will be interpreted as units of the coordinate system of this projection. Otherwise the distance is interpereted as meters and the buffering is 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 buffer method to the Polygon object.
var polygonBuffer = polygon.buffer({'distance': 100});

// Print the result to the console.
print('polygon.buffer(...) =', polygonBuffer);

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

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 buffer method to the Polygon object.
polygon_buffer = polygon.buffer(distance=100)

# Print the result.
display('polygon.buffer(...) =', polygon_buffer)

# 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_buffer, {'color': 'red'}, 'Result [red]: polygon.buffer')
m