classification.py•2.89 kB
# 空间分类函数
from fastmcp import FastMCP
from turf_mcp.utils import call_js_script
classification_mcp = FastMCP("classification")
@classification_mcp.tool
async def nearestPoint(target_point: str, points: str) -> str:
"""
查找距离目标点最近的点特征。
此功能从点集合中查找距离给定目标点最近的点特征，并返回该点及其距离信息。
Args:
target_point: 目标点特征
- 类型: str (JSON 字符串格式的 GeoJSON Feature)
- 格式: Feature with Point geometry
- 示例: '{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-75.343, 39.984]}}'
points: 点特征集合
- 类型: str (JSON 字符串格式的 GeoJSON FeatureCollection)
- 格式: FeatureCollection with Point features
- 示例: '{"type": "FeatureCollection", "features": [{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-75.833, 39.284]}}, ...]}'
Returns:
str: JSON 字符串格式的最近点特征
- 类型: GeoJSON Feature with Point geometry and distance property
- 格式: {"type": "Feature", "geometry": {"type": "Point", "coordinates": [lng, lat]}, "properties": {"distance": 距离数值, ...}}
- 示例: '{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-75.833, 39.284]}, "properties": {"distance": 12.34, ...}}'
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
>>> target_point = '{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-75.343, 39.984]}}'
>>> points = '{"type": "FeatureCollection", "features": [{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-75.833, 39.284]}}]}'
>>> result = asyncio.run(nearestPoint(target_point, points))
>>> print(result)
'{"type": "Feature", "geometry": {"type": "Point", "coordinates": [-75.833, 39.284]}, "properties": {"distance": 12.34, ...}}'
Notes:
- 输入参数 target_point 和 points 必须是有效的 JSON 字符串
- 坐标顺序为 [经度, 纬度] (WGS84 坐标系)
- 计算的是球面距离，单位为千米
- 返回的点特征包含原始属性以及新增的 distance 属性
- 依赖于 Turf.js 库和 Node.js 环境
"""
js_script = f"""
const turf = require('@turf/turf');
const targetPoint = JSON.parse('{target_point}');
const points = JSON.parse('{points}');
const result = turf.nearestPoint(targetPoint, points);
console.log(JSON.stringify(result));
"""
try:
return await call_js_script(js_script)
except Exception as e:
raise Exception(f"执行异常: {str(e)}")