ee.Geometry.MultiPolygon.difference

返回从“左侧”几何图形中减去“右侧”几何图形的结果。

用法	返回
MultiPolygon.difference(right, maxError, proj)	几何图形

参数	类型	详细信息
此：left	几何图形	用作运算左操作数的几何图形。
right	几何图形	用作相应运算的右操作数的几何图形。
maxError	ErrorMargin，默认值：null	执行任何必要的重新投影时可容忍的最大误差量。
proj	投影，默认值：null	执行操作的投影。如果未指定，则操作将在球面坐标系中执行，并且球面上的直线距离将以米为单位。

示例

代码编辑器 (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]]]]);

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

// Apply the difference method to the MultiPolygon object.
var multiPolygonDifference = multiPolygon.difference({'right': inputGeom, 'maxError': 1});

// Print the result to the console.
print('multiPolygon.difference(...) =', multiPolygonDifference);

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

Python 设置

如需了解 Python API 和如何使用 geemap 进行交互式开发，请参阅 Python 环境页面。

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]]],
])

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

# Apply the difference method to the MultiPolygon object.
multipolygon_difference = multipolygon.difference(right=input_geom, maxError=1)

# Print the result.
display('multipolygon.difference(...) =', multipolygon_difference)

# 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(input_geom, {'color': 'blue'}, 'Parameter [blue]: input_geom')
m.add_layer(
    multipolygon_difference,
    {'color': 'red'},
    'Result [red]: multipolygon.difference',
)
m