坐标转换

1、将米转换成坐标度数

function getRadiusByMile(raidusMile){
    var radius = 0;
    var degree = (24901*1609)/360.0;
    var draidusMile = raidusMile;
    var dpm = 1/degree;
    radius = dpm*draidusMile;
    return radius;
}

2、根据坐标点和半径将地图缩放到合适等级

var x;
var y;
var radius = parseInt($(".bufferRidius").val());
var r = getRadiusByMile(radius); //前面的算法

var rectArr = [];
var leftBottom = [x-r,y-r];
var leftTop = [x+r,y-r]; 
var righttBottom = [x+r,y-r]; 
var rightTop = [x+r,y+r]; 
rectArr = [leftBottom,leftTop,rightTop,righttBottom];
top.setFitResolutionAdmin(rectArr);

//设置最佳可视范围[[x,y],[x,y],[x,y]]
function setFitResolutionAdmin(pointsArr){
    var  lineStr =  new  ol.geom.LineString(pointsArr);
    if (map){
        var view =  map.getView();
        var res = view.fit(lineStr);
        mapZoom(1);  //地图缩小两级
    }else{
        console.log("地图还未初始化完成")
    }  
}