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ee.Geometry.LineString.length
透過集合功能整理內容
你可以依據偏好儲存及分類內容。
傳回幾何的線性部分長度。系統會忽略多邊形部分。多重幾何圖形的長度是其元件長度的總和。
用量 | 傳回 |
---|
LineString.length(maxError, proj) | 浮點值 |
引數 | 類型 | 詳細資料 |
---|
這個:geometry | 幾何圖形 | 輸入幾何圖形。 |
maxError | ErrorMargin,預設值:null | 執行任何必要重投影時可容許的最大誤差量。 |
proj | 投影,預設值:null | 如果指定,結果會以這個投影的座標系統單位表示。否則單位為公尺。 |
範例
程式碼編輯器 (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 設定
請參閱
Python 環境頁面,瞭解 Python API 和如何使用 geemap
進行互動式開發。
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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上次更新時間:2025-07-26 (世界標準時間)。
[null,null,["上次更新時間:2025-07-26 (世界標準時間)。"],[[["\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```"]]