openlayers 判断geojson文件是否在视口内

openlayers 判断geojson文件是否在视口内

import GeoJSON from 'ol/format/GeoJSON'
import { createEmpty, extend, containsExtent, intersects } from 'ol/extent'/*** 判断geojson文件是否在视口内* @param {*} map* @param {*} geojsonData geojson数据*/judgeGeojsonIsInViewport(map, geojsonData) {if (map && geojsonData) {// 获取当前视口范围（以投影坐标表示）const viewportExtent = map.getView().calculateExtent(map.getSize())const format = new GeoJSON()const features = format.readFeatures(geojsonData, {featureProjection: map.getView().getProjection(),})// 计算GeoJSON所有要素的总范围const totalExtent = createEmpty()features.forEach((feature) => {extend(totalExtent, feature.getGeometry().getExtent())})// 判断总范围是否与视口相交const isVisible = intersects(viewportExtent, totalExtent)return isVisible}return false}