概述

在做编辑的时候，难免会遇到多边形的分割问题，本文用turf.js实现此功能。

效果

实现思路

实现代码

function polygonCut(poly, line, tolerance = .001, toleranceType ='kilometers') {// 1. 条件判断if (poly.geometry === void 0 || poly.geometry.type !== 'Polygon')throw ('传入的必须为polygon');if (line.geometry === void 0 || line.geometry.type.toLowerCase().indexOf('linestring') === -1)throw ('传入的必须为linestring');if (line.geometry.type === "LineString") {if (turf.booleanPointInPolygon(turf.point(line.geometry.coordinates[0]), poly)|| turf.booleanPointInPolygon(turf.point(line.geometry.coordinates[line.geometry.coordinates.length - 1]), poly))throw ('起点和终点必须在多边形之外');}// 2. 计算交点，并把线的点合并let lineIntersect = turf.lineIntersect(line, poly);const lineExp = turf.explode(line);for (let i = 0; i < lineExp.features.length - 1; i++) {lineIntersect.features.push(turf.point(lineExp.features[i].geometry.coordinates));}// 3. 计算线的缓冲区const lineBuffer = turf.buffer(line, tolerance, {units: toleranceType});// 4. 计算线缓冲和多边形的difference，返回"MultiPolygon"，所以将其拆开const _body = turf.difference(poly, lineBuffer);let pieces = [];if (_body.geometry.type === 'Polygon') {pieces.push(turf.polygon(_body.geometry.coordinates));} else {_body.geometry.coordinates.forEach(function (a) { pieces.push(turf.polygon(a)) });}// 5. 处理点数据for (p in pieces) {const piece = pieces[p];for (let c in piece.geometry.coordinates[0]) {const coord = piece.geometry.coordinates[0][c];const p = turf.point(coord);for (let lp in lineIntersect.features) {const lpoint = lineIntersect.features[lp];if (turf.distance(lpoint, p, toleranceType) <= tolerance*2) {piece.geometry.coordinates[0][c] = lpoint.geometry.coordinates;}}}}// 6. 过滤掉重复点for (p in pieces) {const coords = pieces[p].geometry.coordinates[0]pieces[p].geometry.coordinates[0] = filterDuplicatePoints(coords);}// 7. 将属性赋予每一个polygon，并处理idpieces.forEach((a, index) => {a.properties = Object.assign({}, poly.properties)a.properties.id += `-${index}`});return turf.featureCollection(pieces);
}