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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成品图:
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:http://dev.baidu.com/wiki/map/index.php?title=MapLibrary
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(116.387452,39.947302); 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); //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:http://dev.baidu.com/wiki/map/index.php?title=MapLibrary
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.length;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(116.279655,40.020499), 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);
本例全部源代码:
<!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> <title>社交地图</title> <script type="text/javascript" src="http://api.map.baidu.com/api?v=1.2"></script> <script type="text/javascript" src="http://api.map.baidu.com/library/GeoUtils/1.2/src/GeoUtils_min.js"></script> </head> <body> <div style="width:520px;height:340px;border:1px solid gray" id="container"></div> <div style="width:200px;height:340px;border: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.length;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>
2012-02-07 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.length;i++){ var result = BMapLib.GeoUtils.isPointInRect(markers[i].point, map.getBounds()); if(result == true && j<10) { map.addOverlay(markers[i]); ++j; } else if(result == true && j>=10){ ++j; document.getElementById("info").innerHTML = "可视区域内的用户数:</br><b style='color:red;font-size:50px'>" + j + "</b>"; map.removeOverlay(markers[i]); } else map.removeOverlay(markers[i]); } }