I think it's not you but the server layer who's causing the error
(assuming that you refer to 'jpl_wms' layer). If you replace 'landsat7'
layer with 'overview' layer you'll notice that there's no error, just a
blank image, which means that even the server is OK but not is the
layer. You would try with another WMS server<br>
<br clear="all">Best regards,<br><br>Xurxo Méndez Pérez<br><br><a href="http://www.sonxurxo.com/" target="_blank">http://www.sonxurxo.com</a><br>
<br><br><div class="gmail_quote">2010/10/28 Malik Shahzad <span dir="ltr"><<a href="mailto:malik.rsgis@gmail.com">malik.rsgis@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div class="gmail_quote">Dear I am new to Open layers and need some information.<div><br></div><div>I am trying to add some WMS layers but failed to do :( I am following one tutorial and write following code.</div><div><br>
</div><div><br></div><div><div><html></div><div><span style="white-space: pre-wrap;"> </span><head></div><div><span style="white-space: pre-wrap;"> </span><title>OpenLayers Example</title></div>
<div><span style="white-space: pre-wrap;"> </span><script src="<a href="http://openlayers.org/api/OpenLayers.js" target="_blank">http://openlayers.org/api/OpenLayers.js</a>"></script></div><div><span style="white-space: pre-wrap;"> </span><script defer="defer" type="text/javascript"></div>
<div><span style="white-space: pre-wrap;"> </span>function init()</div><div><span style="white-space: pre-wrap;"> </span>{</div><div><span style="white-space: pre-wrap;"> </span>var map = new OpenLayers.Map('map');</div>
<div><span style="white-space: pre-wrap;"> </span>var wms = new OpenLayers.Layer .WMS( "OpenLayers WMS",</div><div><span style="white-space: pre-wrap;"> </span>"<a href="http://labs.metacarta.com/wms/vmap0" target="_blank">http://labs.metacarta.com/wms/vmap0</a>",</div>
<div><span style="white-space: pre-wrap;"> </span>{layers: 'basic'}</div><div><span style="white-space: pre-wrap;"> </span>);</div><div><span style="white-space: pre-wrap;"> </span>map.addLayer (wms);</div>
<div><span style="white-space: pre-wrap;"> </span>map.zoomToMaxExtent();</div><div><br></div><div><span style="white-space: pre-wrap;"> </span>var lon = 100.4;</div><div><span style="white-space: pre-wrap;"> </span>var lat = 13.1;</div>
<div><span style="white-space: pre-wrap;"> </span>var zoom = 5;</div><div><span style="white-space: pre-wrap;"> </span>map.setCenter(new OpenLayers.LonLat(lon, lat), zoom);</div><div><br></div>
<div><br></div><div><span style="white-space: pre-wrap;"> </span>map.addControl( new OpenLayers.Control.LayerSwitcher() );</div><div><br></div><div><span style="white-space: pre-wrap;"> </span>var jpl_wms = new OpenLayers.Layer.WMS( "NASA Global Mosaic",</div>
<div><span style="white-space: pre-wrap;"> </span>"<a href="http://t1.hypercube.telascience.org/cgi-bin/landsat7" target="_blank">http://t1.hypercube.telascience.org/cgi-bin/landsat7</a>" ,</div><div><span style="white-space: pre-wrap;"> </span>{layers: "landsat7"}</div>
<div><span style="white-space: pre-wrap;"> </span>);</div><div><span style="white-space: pre-wrap;"> </span>map.addLayer(jpl_wms);</div><div><span style="white-space: pre-wrap;"> </span>}</div>
<div><br></div><div><span style="white-space: pre-wrap;"> </span></script></div><div><span style="white-space: pre-wrap;"> </span></head></div><div><br></div><div><body onload=init()></div>
<div><br></div><div><div style="width: 800px; height: 475px" id="map"></div><div><br></div><div>Hello My Map</div><div><br></div><div></div></div><div></body></div><div></html></div>
</div><div><br></div><div><br></div><div><br></div><div><br></div>
<div>waiting for your kind response.</div><div>Malik</div>
</div><br>
<br>_______________________________________________<br>
Dev mailing list<br>
<a href="mailto:Dev@lists.osgeo.org">Dev@lists.osgeo.org</a><br>
<a href="http://lists.osgeo.org/mailman/listinfo/openlayers-dev" target="_blank">http://lists.osgeo.org/mailman/listinfo/openlayers-dev</a><br>
<br></blockquote></div><br>