OpenLayers学习——Style及StyleMap（二）

参考官网例子，做一个随比例一起缩放的矢量符号的例子，主要代码如下：

<script type="text/javascript">
        var map;
        function init() {
            var options = {
                controls: [],
                maxResolution: "auto"
            };
            map = new OpenLayers.Map("map", options);

            var wms = new OpenLayers.Layer.WMS("WMS",
                "http://vmap0.tiles.osgeo.org/wms/vmap0", { layers: 'basic' });
            map.addLayer(wms);
            // 初始化空间
            map.addControl(new OpenLayers.Control.ZoomPanel());
            map.addControl(new OpenLayers.Control.Navigation());
            map.addControl(new OpenLayers.Control.MousePosition());

            var renderer = OpenLayers.Util.getParameters(window.location.href).renderer;
            renderer = (renderer) ? [renderer] : OpenLayers.Layer.Vect