摘要：如果你自己的数据已经超过1万个，如何进行合理的显示？除了聚合marker外，还有一个办法。那就是，只显示可视区域内的标注。
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工具描述：
移动地图时（或改变地图级别时），只显示可视区域内的标注。非可视区域内的标注都移除。
这样可以保持高效的系统性能。
另外，可视区域内的标注，请保持在200以内。各类浏览器方能高效地显示。
如果有超过300个marker，建议使用聚合marker类，请参考LIB：
1、从数据库里读取信息
数据库里需要存储的信息至少为：经纬度point，标注图片icon。
读取后，创建点、标注。（注意：只是创建标注，并不添加到地图上。）
//创建10个点var p1 = new BMap.Point(116..947302);var p2 = new BMap.Point(116..961129);var p3 = new BMap.Point(116..960133);var p4 = new BMap.Point(116..919528);var p5 = new BMap.Point(116..939557);var p6 = new BMap.Point(116..974511);var p7 = new BMap.Point(116..974511);var p8 = new BMap.Point(116..930484);var p9 = new BMap.Point(116.103);var p0 = new BMap.Point(116..844671);//创建10张图标var icon1 = new BMap.Icon("img/1.jpg", new BMap.Size(50,50));var icon2 = new BMap.Icon("img/2.jpg", new BMap.Size(50,50));var icon3 = new BMap.Icon("img/3.jpg", new BMap.Size(50,50));var icon4 = new BMap.Icon("img/4.jpg", new BMap.Size(50,50));var icon5 = new BMap.Icon("img/5.jpg", new BMap.Size(50,50));var icon6 = new BMap.Icon("img/6.jpg", new BMap.Size(50,50));var icon7 = new BMap.Icon("img/7.jpg", new BMap.Size(50,50));var icon8 = new BMap.Icon("img/8.jpg", new BMap.Size(50,50));var icon9 = new BMap.Icon("img/9.jpg", new BMap.Size(50,50));var icon0 = new BMap.Icon("img/0.jpg", new BMap.Size(50,50));//创建10个marker，但不添加到地图上var m1 = new BMap.Marker(p1,{icon:icon1}); var m2 = new BMap.Marker(p2,{icon:icon2}); var m3 = new BMap.Marker(p3,{icon:icon3}); var m4 = new BMap.Marker(p4,{icon:icon4}); var m5 = new BMap.Marker(p5,{icon:icon5}); var m6 = new BMap.Marker(p6,{icon:icon6}); var m7 = new BMap.Marker(p7,{icon:icon7}); var m8 = new BMap.Marker(p8,{icon:icon8}); var m9 = new BMap.Marker(p9,{icon:icon9}); var m0 = new BMap.Marker(p0,{icon:icon0});
为了方便运算，用一个数组将标注集合起来：
//建立一个marker的数组var markers = [m1,m2,m3,m4,m5,m6,m7,m8,m9,m0,m11,m12,m13,m14,m15,m16,m17,m18,m19,m10,m21,m22,m23,m24,m25,m26,m27,m28,m29,m20];
2、判断标注是否在可视区域内
利用几何运算的LIB可以轻松判断，标注是否在可视区域内。
几何运算LIB：
判断标注如果在可视区域内，则添加到地图上；如果标注不在可视区域内，则删除它。
判断代码：
//显示可视区域内的标注function addMymarkers(){
for(i=0;i&markers.i++){
var result = BMapLib.GeoUtils.isPointInRect(markers[i].point, map.getBounds());
if(result == true) map.addOverlay(markers[i]);
else map.removeOverlay(markers[i]);
3、将可视区域内的标注添加到地图上
在图块加载完毕，地图中心点改变，和地图级别改变时，都需要进行一次添加/移除标注的操作。
//对地图级别变化、移动结束和图块加载完毕后，进行添加marker的操作map.addEventListener("tilesloaded", addMymarkers);map.addEventListener("zoomend", addMymarkers);map.addEventListener("moveend", addMymarkers);
4、给标注的区域画一个框
为了方便观看，我用的是折线覆盖物，你也可以使用多边形覆盖物。
//添加一个矩形覆盖物var polyline = new BMap.Polyline([
new BMap.Point(116..020499),
new BMap.Point(116..833259),
new BMap.Point(116..830599),
new BMap.Point(116..021383),
new BMap.Point(116..020499)], {strokeColor:"blue", strokeWeight:6, strokeOpacity:0.5});map.addOverlay(polyline);
本例全部源代码：
&!DOCTYPE html&&html&&head&&meta http-equiv="Content-Type" content="text/ charset=gb2312" /&&title&社交地图&/title&&script type="text/javascript" src="http://api./api?v=1.2"&&/script&&script type="text/javascript" src="http://api./library/GeoUtils/1.2/src/GeoUtils_min.js"&&/script&&/head&&body&&div style="width:520height:340border:1px solid gray" id="container"&&/div&&div style="width:200height:340border:1px solid gray" id="info"&&/div&&p id="info"&&/p&&/body&&/html&&script type="text/javascript"&//创建地图var map = new BMap.Map("container");map.centerAndZoom(new BMap.Point(116.387452,39.947302), 13);//添加一个矩形覆盖物var polyline = new BMap.Polyline([
new BMap.Point(116.279655,40.020499),
new BMap.Point(116.260683,39.833259),
new BMap.Point(116.532043,39.830599),
new BMap.Point(116.526869,40.021383),
new BMap.Point(116.279655,40.020499)], {strokeColor:"blue", strokeWeight:6, strokeOpacity:0.5});map.addOverlay(polyline);//显示可视区域内的标注function addMymarkers(){
document.getElementById("info").innerHTML = '';
for(i=0;i&markers.i++){
var result = BMapLib.GeoUtils.isPointInRect(markers[i].point, map.getBounds());
if(result == true) map.addOverlay(markers[i]);
else map.removeOverlay(markers[i]);
document.getElementById("info").innerHTML += '&img src="' + markers[i].getIcon().imageUrl +'" /&';
//对地图级别变化、移动结束和图块加载完毕后，进行添加marker的操作map.addEventListener("tilesloaded", addMymarkers);map.addEventListener("zoomend", addMymarkers);map.addEventListener("moveend", addMymarkers);//创建30个点var p1 = new BMap.Point(116.387452,39.947302);var p2 = new BMap.Point(116.361581,39.961129);var p3 = new BMap.Point(116.437901,39.960133);var p4 = new BMap.Point(116.459748,39.919528);var p5 = new BMap.Point(116.424247,39.939557);var p6 = new BMap.Point(116.485188,39.974511);var p7 = new BMap.Point(116.485188,39.974511);var p8 = new BMap.Point(116.494243,39.930484);var p9 = new BMap.Point(116.45328,39.884103);var p0 = new BMap.Point(116.456011,39.844671);var p11 = new BMap.Point(116.387165,39.850654);var p12 = new BMap.Point(116.461185,39.8975);var p13 = new BMap.Point(116.380122,39.87458);var p14 = new BMap.Point(116.354395,39.899825);var p15 = new BMap.Point(116.394495,39.887093);var p16 = new BMap.Point(116.30524,39.902482);var p17 = new BMap.Point(116.287992,39.937676);var p18 = new BMap.Point(116.277931,39.911116);var p19 = new BMap.Point(116.340166,39.929267);var p10 = new BMap.Point(116.290004,39.965885);var p21 = new BMap.Point(116.377535,39.966548);var p22 = new BMap.Point(116.423672,39.95239);var p23 = new BMap.Point(116.423672,39.95239);var p24 = new BMap.Point(116.300353,40.003146);var p25 = new BMap.Point(116.294172,39.982251);var p26 = new BMap.Point(116.313432,39.977497);var p27 = new BMap.Point(116.390183,39.983357);var p28 = new BMap.Point(116.390183,39.983357);var p29 = new BMap.Point(116.484469,39.943872);var p20 = new BMap.Point(116.509191,39.932586);//创建30张图标var icon1 = new BMap.Icon("img/1.jpg", new BMap.Size(50,50));var icon2 = new BMap.Icon("img/2.jpg", new BMap.Size(50,50));var icon3 = new BMap.Icon("img/3.jpg", new BMap.Size(50,50));var icon4 = new BMap.Icon("img/4.jpg", new BMap.Size(50,50));var icon5 = new BMap.Icon("img/5.jpg", new BMap.Size(50,50));var icon6 = new BMap.Icon("img/6.jpg", new BMap.Size(50,50));var icon7 = new BMap.Icon("img/7.jpg", new BMap.Size(50,50));var icon8 = new BMap.Icon("img/8.jpg", new BMap.Size(50,50));var icon9 = new BMap.Icon("img/9.jpg", new BMap.Size(50,50));var icon0 = new BMap.Icon("img/0.jpg", new BMap.Size(50,50));var icon11 = new BMap.Icon("img/11.jpg", new BMap.Size(50,50));var icon12 = new BMap.Icon("img/12.jpg", new BMap.Size(50,50));var icon13 = new BMap.Icon("img/13.jpg", new BMap.Size(50,50));var icon14 = new BMap.Icon("img/14.jpg", new BMap.Size(50,50));var icon15 = new BMap.Icon("img/15.jpg", new BMap.Size(50,50));var icon16 = new BMap.Icon("img/16.jpg", new BMap.Size(50,50));var icon17 = new BMap.Icon("img/17.jpg", new BMap.Size(50,50));var icon18 = new BMap.Icon("img/18.jpg", new BMap.Size(50,50));var icon19 = new BMap.Icon("img/19.jpg", new BMap.Size(50,50));var icon10 = new BMap.Icon("img/10.jpg", new BMap.Size(50,50));var icon21 = new BMap.Icon("img/21.jpg", new BMap.Size(50,50));var icon22 = new BMap.Icon("img/22.jpg", new BMap.Size(50,50));var icon23 = new BMap.Icon("img/23.jpg", new BMap.Size(50,50));var icon24 = new BMap.Icon("img/24.jpg", new BMap.Size(50,50));var icon25 = new BMap.Icon("img/25.jpg", new BMap.Size(50,50));var icon26 = new BMap.Icon("img/26.jpg", new BMap.Size(50,50));var icon27 = new BMap.Icon("img/27.jpg", new BMap.Size(50,50));var icon28 = new BMap.Icon("img/28.jpg", new BMap.Size(50,50));var icon29 = new BMap.Icon("img/29.jpg", new BMap.Size(50,50));var icon20 = new BMap.Icon("img/20.jpg", new BMap.Size(50,50));//创建30个marker，但不添加到地图上var m1 = new BMap.Marker(p1,{icon:icon1}); var m2 = new BMap.Marker(p2,{icon:icon2}); var m3 = new BMap.Marker(p3,{icon:icon3}); var m4 = new BMap.Marker(p4,{icon:icon4}); var m5 = new BMap.Marker(p5,{icon:icon5}); var m6 = new BMap.Marker(p6,{icon:icon6}); var m7 = new BMap.Marker(p7,{icon:icon7}); var m8 = new BMap.Marker(p8,{icon:icon8}); var m9 = new BMap.Marker(p9,{icon:icon9}); var m0 = new BMap.Marker(p0,{icon:icon0}); var m11 = new BMap.Marker(p11,{icon:icon11}); var m12 = new BMap.Marker(p12,{icon:icon12}); var m13 = new BMap.Marker(p13,{icon:icon13}); var m14 = new BMap.Marker(p14,{icon:icon14}); var m15 = new BMap.Marker(p15,{icon:icon15}); var m16 = new BMap.Marker(p16,{icon:icon16}); var m17 = new BMap.Marker(p17,{icon:icon17}); var m18 = new BMap.Marker(p18,{icon:icon18}); var m19 = new BMap.Marker(p19,{icon:icon19}); var m10 = new BMap.Marker(p10,{icon:icon10}); var m21 = new BMap.Marker(p21,{icon:icon21}); var m22 = new BMap.Marker(p22,{icon:icon22}); var m23 = new BMap.Marker(p23,{icon:icon23}); var m24 = new BMap.Marker(p24,{icon:icon24}); var m25 = new BMap.Marker(p25,{icon:icon25}); var m26 = new BMap.Marker(p26,{icon:icon26}); var m27 = new BMap.Marker(p27,{icon:icon27}); var m28 = new BMap.Marker(p28,{icon:icon28}); var m29 = new BMap.Marker(p29,{icon:icon29}); var m20 = new BMap.Marker(p20,{icon:icon20}); //建立一个marker的数组var markers = [m1,m2,m3,m4,m5,m6,m7,m8,m9,m0,m11,m12,m13,m14,m15,m16,m17,m18,m19,m10,m21,m22,m23,m24,m25,m26,m27,m28,m29,m20];&/script&
&更新代码：修改addMymarkers函数。
当可视区域内的标注大于10的时候，只显示10个标注。并在右侧显示，可视区域内共有多少用户。
部分源代码：
//显示可视区域内的标注function addMymarkers(){
document.getElementById("info").innerHTML = "小于10个用户";
var j = 0;
for(i=0;i&markers.i++){
var result = BMapLib.GeoUtils.isPointInRect(markers[i].point, map.getBounds());
if(result == true && j&10) {
map.addOverlay(markers[i]);
else if(result == true && j&=10){
document.getElementById("info").innerHTML = "可视区域内的用户数：&/br&&b style='color:font-size:50px'&" + j + "&/b&";
map.removeOverlay(markers[i]);
else map.removeOverlay(markers[i]);
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