transformation_concave
Calculate concave hulls from point sets to define irregular boundaries in geospatial data analysis. This tool processes GeoJSON point collections and generates polygon shapes that capture the outer edges of clustered points.
Instructions
计算点集的凹包。
该函数使用 Turf.js 库的 concave 方法，从一组点生成凹包多边形。
Args: points: 点集 GeoJSON FeatureCollection - 类型: str (JSON 字符串格式的 GeoJSON) - 格式: 必须符合 GeoJSON FeatureCollection 规范，包含 Point 特征 - 坐标系: WGS84 (经度在前，纬度在后) - 示例: '{"type": "FeatureCollection", "features": [{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-63.601226, 44.642643]}}, ...]}'
options: 可选参数配置
- 类型: str (JSON 字符串) 或 None
- 可选字段:
- maxEdge: 凹包边缘的最大长度 (默认: Infinity)
- units: 距离单位 (默认: 'kilometers')
- 有效值: 'miles', 'nauticalmiles', 'kilometers', 'meters', 'yards', 'feet', 'inches'
- 示例: '{"maxEdge": 1, "units": "miles"}'Returns: str: JSON 字符串格式的凹包 GeoJSON Polygon 或 MultiPolygon 特征 - 类型: GeoJSON Feature with Polygon or MultiPolygon geometry - 格式: {"type": "Feature", "geometry": {"type": "Polygon", "coordinates": [...]}} 或 null（如果无法计算） - 示例: '{"type": "Feature", "geometry": {"type": "Polygon", "coordinates": [[[-63.6, 44.64], [-63.59, 44.65], ...]]}}'
Raises: Exception: 当 JavaScript 执行失败、超时或输入数据格式错误时抛出异常
Example: >>> import asyncio >>> points = '{"type": "FeatureCollection", "features": [{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-63.601226, 44.642643]}}]}' >>> options = '{"maxEdge": 1, "units": "miles"}' >>> result = asyncio.run(concave(points, options)) >>> print(result) '{"type": "Feature", "geometry": {"type": "Polygon", "coordinates": [[[-63.6, 44.64], [-63.59, 44.65], ...]]}}'
Notes: - 输入参数 points 和 options 必须是有效的 JSON 字符串 - 坐标顺序为 [经度, 纬度] (WGS84 坐标系) - 内部使用 turf-tin 生成几何图形 - 如果无法计算凹包，返回 null - 依赖于 Turf.js 库和 Node.js 环境
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| points | Yes | ||
| options | No |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |