添加叠加 WMS 时出错答案

【问题标题】：Getting error when I adding an Overlay WMS添加叠加 WMS 时出错
【发布时间】：2015-12-21 10:43:58
【问题描述】：

我是 GIS 新手，正在编写我的 openLayer 教程。

这是 HTML 代码：

<html>
    <head>
        <meta charset="utf-8" />
        <meta name="format-detection" content="telephone=no" />
        <meta name="msapplication-tap-highlight" content="no" />
        <!-- WARNING: for iOS 7, remove the width=device-width and height=device-height attributes. See https://issues.apache.org/jira/browse/CB-4323 -->
        <meta name="viewport" content="user-scalable=no, initial-scale=1, maximum-scale=1, minimum-scale=1, width=device-width, height=device-height, target-densitydpi=device-dpi" />
        <link rel="stylesheet" type="text/css" href="css/index.css" />
        <title>Hello World</title>
    </head>
    <body>
        <div class="app">

            <div style="width:100%; height:100%" id="map"></div>
        </div>

        <script type="text/javascript" src="cordova.js"></script>
        <script type="text/javascript" src="js/index.js"></script>
        <script src="http://openlayers.org/api/OpenLayers.js"></script>
        <script type="text/javascript">
            app.initialize();
        </script>
    </body>
</html>

这里是 JavaScript 代码：

var app = {
    // Application Constructor
    initialize: function () {
        //this.bindEvents();

    var map = new OpenLayers.Map('map');
    var wms = new OpenLayers.Layer.WMS("OpenLayers WMS", "http://vmap0.tiles.osgeo.org/wms/vmap0", { layers: 'basic' });

    var dm_wms = new OpenLayers.Layer.WMS(
                    "Canadian Data",
                    "http://www2.dmsolutions.ca/cgi-bin/mswms_gmap",
                    {
                        layers: "bathymetry,land_fn,park,drain_fn,drainage," +
                                "prov_bound,fedlimit,rail,road,popplace",
                        transparent: "true",
                        format: "image/png"
                    },
                    { isBaseLayer: false }
                );

    var vectorLayer = new OpenLayers.Layer.Vector("Overlay");
    var feature = new OpenLayers.Feature.Vector(
     new OpenLayers.Geometry.Point(-71, 4),
     { some: 'data' },
     {
         externalGraphic: 'img/location_fav.png',
         graphicHeight: 21,
         graphicWidth: 16
     });
    vectorLayer.addFeatures(feature);

    map.addLayers([wms, dm_wms, vectorLayer]);
    map.zoomToMaxExtent();
}

};

在浏览器中查看：

我收到此错误：

http://www2.dmsolutions.ca/cgi-bin/mswms_gmap?LAYERS=bathymetry%2Cland_fn%2…EST=GetMap&STYLES=&SRS=EPSG%3A4326&BBOX=-180,-90,0,90&WIDTH=256&HEIGHT=256 Failed to load resource: net::ERR_NAME_NOT_RESOLVED

如果我从 javascript 中删除此行：

var dm_wms = new OpenLayers.Layer.WMS(
                "Canadian Data",
                "http://www2.dmsolutions.ca/cgi-bin/mswms_gmap",
                {
                    layers: "bathymetry,land_fn,park,drain_fn,drainage," +
                            "prov_bound,fedlimit,rail,road,popplace",
                    transparent: "true",
                    format: "image/png"
                },
                { isBaseLayer: false }
            );

我在浏览器上看到了这个视图：

知道为什么我在尝试覆盖图层时会收到上述错误吗？

【问题讨论】：

标签： gis openlayers

【解决方案1】：

服务器“http://www2.dmsolutions.ca/cgi-bin/mswms_gmap”似乎已关闭，请尝试使用另一个 WMS，例如 http://129.206.228.72/cached/osm

var dm_wms = new OpenLayers.Layer.WMS(
            "OSM example",
            "http://129.206.228.72/cached/osm?",
            {
                layers: "osm_auto:all"
                transparent: "true",
                format: "image/png"
            },
            { isBaseLayer: false }
        );

【讨论】：