openlayers交互之线

一、地图上添加线控件：

1、css：

        div.olControlPanel
        {
            top: 0px;
            left: 50px;
            position: absolute;
        }
       
        .olControlPanel div
        {
            display: block;
            24px;
            height: 24px;
            margin: 5px;
            background-color: white;
        }
       
        .olControlPanel .olControlMouseDefaultsItemActive
        {
            background-color: blue;
            background-image: url("http://www.cnblogs.com/OpenLayers/theme/default/img/pan_on.png");
        }
        .olControlPanel .olControlMouseDefaultsItemInactive
        {
            background-color: orange;
            background-image: url("http://www.cnblogs.com/OpenLayers/theme/default/img/pan_off.png");
        }
        .olControlPanel .olControlDrawFeatureItemActive
        {
            24px;
            height: 22px;
            background-image: url("http://www.cnblogs.com/OpenLayers/theme/default/img/draw_line_on.png");
        }
        .olControlPanel .olControlDrawFeatureItemInactive
        {
            24px;
            height: 22px;
            background-image: url("http://www.cnblogs.com/OpenLayers/theme/default/img/draw_line_off.png");
        }

2、js：

function init(){

  lineLayer = new OpenLayers.Layer.Vector("画线");
            map.addLayer(lineLayer);

            panel = new OpenLayers.Control.Panel();
          

            panel.addControls([new OpenLayers.Control.MouseDefaults(),
                 new OpenLayers.Control.DrawFeature(lineLayer, OpenLayers.Handler.Path,
                    { title: '画线' })]);

            map.addControl(panel);

}

  function toggleControl() {
                panel.deactivate();
        }

二、保存线经纬度：

function getData(){

 var line = lineLayer;
            var linelist;
            var list, i, j;
            if (line != null && line.features.length > 0) {
                for (i = 0; i < line.features.length; i++) {
                    list = "";
                    if (line.features[i].geometry.CLASS_NAME == "OpenLayers.Geometry.LineString") {
                        list = line.features[i].geometry.components;

                        for (j = 0; j < list.length; j++) {
                            if (linelist == null || linelist == "") {
                                linelist = i + ":";  //记录第几条线的点
                            }
                            else {
                                linelist += i + ":";  //记录第几条线的点
                            }
                            linelist += list[j].x + ","; //记录经度
                            linelist += list[j].y + ",";  //记录维度
                            linelist += j + ";"; //记录线的第几个点
                        }
                        linelist += "|";
                    }
                }
            }

}

三、根据经纬度绘制线：

function draw(){

if (drawlayer != null) {
                map.removeLayer(drawlayer);
            }
            drawlayer = new OpenLayers.Layer.Vector("画图");
            map.addLayer(drawlayer);

            if (data != null && data.length > 0) {
 
                var pointList = [];

                var lineFeature;
                for (var i = 0; i < data.length; i++) {
                  
    
                        var ll = new OpenLayers.LonLat(data[i].Lon, data[i].Lat);
                        var newPoint = new OpenLayers.Geometry.Point(ll.lon, ll.lat);
                        pointList.push(newPoint);

        }
                
                                lineFeature = new OpenLayers.Feature.Vector(
                new OpenLayers.Geometry.LineString(pointList));
                            
                                    drawlayer.addFeatures([lineFeature]);
            
                            pointList.clear();

}