// 創(chuàng)建圍繞 TCU 大學(xué)的 2 英里緩沖區(qū)
const tcu = turf.point([-97.364, 32.708]);
const buffered = turf.buffer(tcu, 2, {units: 'miles'});

// 可視化：紫色半透明緩沖區(qū)
// 用途：學(xué)校服務(wù)范圍、噪音影響區(qū)域、配送范圍

// 計算紐約和倫敦之間的距離
const from = turf.point([-74.0060, 40.7128]); // 紐約
const to = turf.point([-0.1278, 51.5074]);   // 倫敦

const distance = turf.distance(from, to, {units: 'kilometers'});
console.log(distance); // 約 5570 公里

// 支持單位：degrees, radians, miles, kilometers

// 查找與緩沖區(qū)相交的所有人口普查區(qū)
const filtered = turf.filter(tracts, bufferZone, {
  predicate: 'intersects' // 或 'within', 'contains', 'crosses', 'disjoint'
});

// 幾何中心（幾何中心點）
const centroid = turf.centroid(polygon);

// 質(zhì)心（面積加權(quán)中心，適用于不規(guī)則形狀）
const centerOfMass = turf.centerOfMass(polygon);

// 兩者可能不同：對于不規(guī)則多邊形，質(zhì)心更準確

// 為一系列點創(chuàng)建凸包
const points = turf.featureCollection([
  turf.point([-76, 39]),
  turf.point([-76, 41]),
  turf.point([-78, 40]),
  turf.point([-77, 38])
]);

const hull = turf.convexHull(points);
// 結(jié)果：包圍所有點的最小凸多邊形

// 為一系列點生成 Voronoi 圖
const points = turf.featureCollection([...]); // 多個點
const voronoi = turf.voronoi(points, {
  bbox: [-77, 38, -76, 40] // 邊界框
});

// 每個多邊形代表該點的"影響區(qū)域"

// 創(chuàng)建兩個重疊的緩沖區(qū)
const buffer1 = turf.buffer(point1, 1, {units: 'miles'});
const buffer2 = turf.buffer(point2, 1, {units: 'miles'});

// 計算重疊區(qū)域
const intersection = turf.intersect(buffer1, buffer2);

// 如果無重疊，返回 null

const union = turf.union(polygon1, polygon2, polygon3);
// 結(jié)果：所有多邊形合并后的單一多邊形

const difference = turf.difference(protectedArea, developmentZone);
// 結(jié)果：保護區(qū)內(nèi)未開發(fā)的區(qū)域

// 創(chuàng)建點
const point = turf.point([-76.5, 39.5]);

// 創(chuàng)建線
const line = turf.lineString([
  [-76.5, 39.5],
  [-76.4, 39.6],
  [-76.3, 39.7]
]);

// 創(chuàng)建多邊形
const polygon = turf.polygon([[
  [-76.5, 39.5],
  [-76.4, 39.5],
  [-76.4, 39.6],
  [-76.5, 39.6],
  [-76.5, 39.5] // 閉合
]]);

// 創(chuàng)建矩形
const bbox = [-76.5, 39.5, -76.3, 39.7]; // [minX, minY, maxX, maxY]
const rectangle = turf.bboxPolygon(bbox);

// 旋轉(zhuǎn)多邊形
const rotated = turf.rotate(polygon, 45, {pivot: 'center'});

// 縮放
const scaled = turf.transformScale(polygon, 2); // 放大 2 倍

// 平移
const translated = turf.translate(polygon, [1, 1]); // 向東北移動

// 計算點的密度
const density = turf.nearestPointDensity(points, {
  radius: 100,
  units: 'kilometers'
});

// 查找最近點
const nearest = turf.nearestPoint(targetPoint, pointCollection);

// 創(chuàng)建網(wǎng)格
const grid = turf.rectangleGrid(bbox, 1, 1, {units: 'kilometers'});

// 六邊形網(wǎng)格（更適合空間分析）
const hexGrid = turf.hexGrid(bbox, 1, {units: 'kilometers'});

// 計算兩點間的測地線（最短路徑）
const greatCircle = turf.greatCircle(start, end);

// 沿線創(chuàng)建點
const along = turf.along(lineString, 5, {units: 'kilometers'});
// 返回從起點開始 5 公里處的點

// 線的長度
const length = turf.length(lineString, {units: 'kilometers'});

npm install @turf/turf

// 導(dǎo)入整個庫
const turf = require('@turf/turf');

// 或按需導(dǎo)入（推薦，減小打包體積）
const buffer = require('@turf/buffer');
const distance = require('@turf/distance');
const intersect = require('@turf/intersect');

<!-- CDN 方式 -->
<script src="https://unpkg.com/@turf/turf@7/turf.min.js"></script>
<script>
  const point = turf.point([-76.5, 39.5]);
  const buffered = turf.buffer(point, 1, {units: 'miles'});
</script>

import { buffer, distance, intersect } from '@turf/turf';

const point = turf.point([-76.5, 39.5]);

// 分析現(xiàn)有站點的覆蓋范圍
const stations = [...]; // 站點位置
const coverage = stations.map(station => 
  turf.buffer(station, 0.5, {units: 'kilometers'}) // 500 米覆蓋
);

// 找出未覆蓋的區(qū)域
const cityBounds = turf.polygon([...]);
const unionCoverage = turf.union(...coverage);
const gaps = turf.difference(cityBounds, unionCoverage);

// 在缺口處建議新站點
const suggestedLocations = turf.centroid(gaps);

// 計算每個醫(yī)院的服務(wù)范圍（15 分鐘車程 ≈ 10 公里）
const hospitals = [...];
const serviceAreas = hospitals.map(h => 
  turf.buffer(h, 10, {units: 'kilometers'})
);

// 查找未被覆蓋的居民區(qū)
const residentialAreas = [...];
const uncovered = residentialAreas.filter(area => 
  !serviceAreas.some(service => turf.booleanIntersects(area, service))
);

// 建議新醫(yī)院位置
const optimalLocation = turf.centerOfMass(turf.union(...uncovered));

// 計算每個社區(qū)的綠地可達性
const parks = [...];
const communities = [...];

communities.forEach(community => {
  const nearbyParks = parks.filter(park => {
    const dist = turf.distance(community, park, {units: 'kilometers'});
    return dist < 0.5; // 500 米內(nèi)有公園
  });
  
  community.properties.greenSpaceAccess = nearbyParks.length > 0;
});

// Shiny/R 或 React 應(yīng)用中的實時空間過濾
map.on('draw:created', (e) => {
  const drawnPolygon = e.layer;
  
  // 立即過濾顯示結(jié)果
  const filtered = turf.filter(allFeatures, drawnPolygon, {
    predicate: 'intersects'
  });
  
  // 即時更新地圖顯示
  updateMapLayer(filtered);
});