Hi,
the problem here is that you configure the OpenLayers map in the wrong mode.
See below:
On Sep 23, 2010, at 21:43 , IT Intern wrote:
> Hello GeoExt users,
>
> This one's gotten me totally stumped. I have some base layers and a few wms
> overlays. When my page loads it shows the base layer for a quick second and
> then goes blank as it loads my overlays. It stays blank until I click the
> map, etc. Then it displays properly. I've Googled all sorts of things
> concerning this sort of issue and have come up with nothing that gives me a
> hint as to why this could be. This never happened to me before until I
> started using GeoExt to display my map. Is it something in code I must write
> for GeoExt or OpenLayers so that this doesnt happen? It's driving me crazy!!!
>
> Code:
>
> //Base Layers
>
> var ghyb = new OpenLayers.Layer.Google(
> "Google Hybrid",
> {type: google.maps.MapTypeId.HYBRID, numZoomLevels: 20}
> );
>
> var gmap = new OpenLayers.Layer.Google(
> "Google Streets", // the default
> {numZoomLevels: 20},{visibility: true}
> );
>
> var osm = new OpenLayers.Layer.OSM();
>
> //.....
> ....
> ....
>
> var options = {
> controls: [new OpenLayers.Control.Navigation()],
> maxExtent: new OpenLayers.Bounds(-20037508.34,
> -20037508.34, 20037508.34, 20037508.34),
> maxResolution: "auto",
> projection: new OpenLayers.Projection("EPSG:900913"),
> units: 'm',
> allOverlays: false
> }
>
>
> var map = new OpenLayers.Map('map', options);
Wrong! If at all, use the following instead:
var map = new OpenLayers.Map(options);
You don't want to render the map at this point, so you have to configure it
without a map div.
> map.addLayers([gmap, ghyb, osm, all_chn, all_tib, chn_bridges,
> tib_bridges, chn_countys, tib_countys, chn_farms, tib_farms, chn_glaciers,
> tib_glaciers, chn_grazing, tib_grazing, chn_hwyCrew, tib_hwyCrew,
> chn_hospitals, tib_hospitals, chn_lakes, tib_lakes, chn_monastaries,
> tib_monastaries, chn_pass, tib_pass, chn_rivers, tib_rivers, chn_townships,
> tib_townships, chn_villages, tib_villages]);
>
> var mapPanel = new GeoExt.MapPanel({
> title: "Map",
> map: map,
Now the preferred way to configure a MapPanel would be to remove the "var map =
..." above entirely, and configure the map here:
map: options,
layers: [gmap, ghyb, osm, all_chn, all_tib, chn_bridges,
tib_bridges, chn_countys, tib_countys, chn_farms, tib_farms, chn_glaciers,
tib_glaciers, chn_grazing, tib_grazing, chn_hwyCrew, tib_hwyCrew,
chn_hospitals, tib_hospitals, chn_lakes, tib_lakes, chn_monastaries,
tib_monastaries, chn_pass, tib_pass, chn_rivers, tib_rivers, chn_townships,
tib_townships, chn_villages, tib_villages]
Regards,
Andreas.
> center: map.setCenter(new OpenLayers.LonLat(93.9,
> 29.53).transform(new OpenLayers.Projection("EPSG:4326"),
> map.getProjectionObject())),
> zoom: 9,
> region: "center",
> bbar: [{
> xtype: "label",
> text: "Scale = 1 : "
> }],
> items: [{
> xtype: "gx_zoomslider",
> vertical: true,
> height: 300,
> x: 10,
> y: 20,
> plugins: new GeoExt.ZoomSliderTip()
> }]
> });
>
> var layerRoot = new Ext.tree.TreeNode({
> text: "All Layers",
> expanded: true,
> autoLoad: true
> });
>
> //Is there something to set here???
> layerRoot.appendChild(new GeoExt.tree.BaseLayerContainer({
> text: "Base Layers",
> map: map,
> layerStore: mapPanel.layers,
> expanded: true,
> autoLoad: true
> }));
>
> //.....
>
> Thank you very much, I appreciate any suggestions :),
>
> elshae
>
>
>
> _______________________________________________
> Users mailing list
> [email protected]
> http://www.geoext.org/cgi-bin/mailman/listinfo/users
--
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.
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