[记录]根据经纬度计算两点间的距离 [记录]根据经纬度计算两点间的

下面是一个根据经纬度计算两点间距离的方法记录：

function rad(d){ return d * Math.PI / 180.0; }module.exports = function getDistance(addr1,addr2,autoFormat = false){ const EARTH_RADIUS = 6378137; const lon1 = addr1.lon; const lat1 = addr1.lat; const lon2 = addr2.lon; const lat2 = addr2.lat; let radLon1 = rad(lon1) let radLon2 = rad(lon2) let radLat1 = rad(lat1) let radLat2 = rad(lat2)if(radLat1 < 0){ radLat1 = Math.PI / 2 + Math.abs(radLat1); // south } if(radLat1 > 0){ radLat1 = Math.PI / 2 - Math.abs(radLat1); // north } if(radLon1 < 0){ radLon1 = Math.PI * 2 - Math.abs(radLon1); // west } if(radLat2 < 0){ radLat2 = Math.PI / 2 + Math.abs(radLat2); // south } if(radLat2 > 0){ radLat2 = Math.PI / 2 - Math.abs(radLat2); // north } if(radLon2 < 0){ radLon2 = Math.PI * 2 - Math.abs(radLon2); // west }const x1 = EARTH_RADIUS * Math.cos(radLon1) * Math.sin(radLat1); const y1 = EARTH_RADIUS * Math.sin(radLon1) * Math.sin(radLat1); const z1 = EARTH_RADIUS * Math.cos(radLat1); const x2 = EARTH_RADIUS * Math.cos(radLon2) * Math.sin(radLat2); const y2 = EARTH_RADIUS * Math.sin(radLon2) * Math.sin(radLat2); const z2 = EARTH_RADIUS * Math.cos(radLat2); const d = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2) + (z1 - z2) * (z1 - z2)); //余弦定理求夹角 const theta = Math.acos((EARTH_RADIUS * EARTH_RADIUS + EARTH_RADIUS * EARTH_RADIUS - d * d) / (2 * EARTH_RADIUS * EARTH_RADIUS)); const dist = (theta * EARTH_RADIUS); if(autoFormat){ if(dist < 1000){ return dist + "m" }else{ return dist / 1000 + "km" } } return dist; }

【[记录]根据经纬度计算两点间的距离】其中，getDistance 接收两个位置信息作为参数，以及一个是否自动格式化的可选参数，当此参数传为 true 时，会对返回值进行转换。
完。