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ee.Geometry.LineString.length
使用集合让一切井井有条
根据您的偏好保存内容并对其进行分类。
返回几何图形的线性部分的长度。多边形部分会被忽略。多几何图形的长度是其组成部分的长度之和。
| 用法 | 返回 |
|---|
LineString.length(maxError, proj) | 浮点数 |
| 参数 | 类型 | 详细信息 |
|---|
此：geometry | 几何图形 | 输入几何图形。 |
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 | 如果指定，结果将采用相应投影的坐标系的单位。否则将以米为单位。 |
示例
代码编辑器 (JavaScript)
// Define a LineString object.
var lineString = ee.Geometry.LineString([[-122.09, 37.42], [-122.08, 37.43]]);
// Apply the length method to the LineString object.
var lineStringLength = lineString.length();
// Print the result to the console.
print('lineString.length(...) =', lineStringLength);
// Display relevant geometries on the map.
Map.setCenter(-122.085, 37.422, 15);
Map.addLayer(lineString,
{'color': 'black'},
'Geometry [black]: lineString');
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 LineString object.
linestring = ee.Geometry.LineString([[-122.09, 37.42], [-122.08, 37.43]])
# Apply the length method to the LineString object.
linestring_length = linestring.length()
# Print the result.
display('linestring.length(...) =', linestring_length)
# Display relevant geometries on the map.
m = geemap.Map()
m.set_center(-122.085, 37.422, 15)
m.add_layer(linestring, {'color': 'black'}, 'Geometry [black]: linestring')
m
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最后更新时间 (UTC)：2025-07-26。
[null,null,["最后更新时间 (UTC)：2025-07-26。"],[[["\u003cp\u003eCalculates the length of the linear portions of a geometry, excluding polygonal areas.\u003c/p\u003e\n"],["\u003cp\u003eReturns the total length of all components for multi-geometries.\u003c/p\u003e\n"],["\u003cp\u003eAccepts optional parameters for error margin (\u003ccode\u003emaxError\u003c/code\u003e) during reprojection and specifying the output projection (\u003ccode\u003eproj\u003c/code\u003e) for unit control.\u003c/p\u003e\n"],["\u003cp\u003eReturns the length in meters by default, or in the units of the specified projection if provided.\u003c/p\u003e\n"]]],["The `length()` method calculates the length of linear parts within a geometry, ignoring polygonal sections. For multi-geometries, it sums the lengths of individual components. It accepts an optional `maxError` argument to specify reprojection tolerance and a `proj` argument to define the output projection. Otherwise the length is in meters. The function is demonstrated in JavaScript and Python, showing how to create a `LineString`, compute its length, and display it on a map.\n"],null,["# ee.Geometry.LineString.length\n\nReturns the length of the linear parts of the geometry. Polygonal parts are ignored. The length of multi geometries is the sum of the lengths of their components.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|----------------------------------------------|---------|\n| LineString.length`(`*maxError* `, `*proj*`)` | Float |\n\n| Argument | Type | Details |\n|------------------|----------------------------|----------------------------------------------------------------------------------------------------------------------------|\n| this: `geometry` | Geometry | The input geometry. |\n| `maxError` | ErrorMargin, default: null | The maximum amount of error tolerated when performing any necessary reprojection. |\n| `proj` | Projection, default: null | If specified, the result will be in the units of the coordinate system of this projection. Otherwise it will be in meters. |\n\nExamples\n--------\n\n### Code Editor (JavaScript)\n\n```javascript\n// Define a LineString object.\nvar lineString = ee.Geometry.LineString([[-122.09, 37.42], [-122.08, 37.43]]);\n\n// Apply the length method to the LineString object.\nvar lineStringLength = lineString.length();\n\n// Print the result to the console.\nprint('lineString.length(...) =', lineStringLength);\n\n// Display relevant geometries on the map.\nMap.setCenter(-122.085, 37.422, 15);\nMap.addLayer(lineString,\n {'color': 'black'},\n 'Geometry [black]: lineString');\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 LineString object.\nlinestring = ee.Geometry.LineString([[-122.09, 37.42], [-122.08, 37.43]])\n\n# Apply the length method to the LineString object.\nlinestring_length = linestring.length()\n\n# Print the result.\ndisplay('linestring.length(...) =', linestring_length)\n\n# Display relevant geometries on the map.\nm = geemap.Map()\nm.set_center(-122.085, 37.422, 15)\nm.add_layer(linestring, {'color': 'black'}, 'Geometry [black]: linestring')\nm\n```"]]
