[OpenLayers-Users] zooming out when changing base layer

[Bart van den Eijnden (OSGIS)]

Hi Erik,

but with WMS Untiled, I do not specify an extent nor a resolution for a
layer.

How does this relate then to WMS Untiled? Is there a way around it?

This is my code:

        function mapinit(){
            map = new OpenLayers.Map( $('map'), { controls: [],
'projection': 'EPSG:28992', 'units':'meters', 'maxExtent': new
OpenLayers.Bounds(-157973.103596, 300670.145842, 472056.321374,
678687.800824) , 'maxResolution':'auto'});            var layer = new
OpenLayers.Layer.WMS.Untiled( "Topografische kaart Nederland",
               
"http://intranet.rijkswaterstaat.nl/services/geoservices/basispakket/topografie?",
{layers: 'AAA126,AAA127,AAA134', 'format':'image/jpeg',
'transparent':'true'}, {'ratio':1, isBaseLayer: true} );

            map.addLayers([layer]);            var layer = new
OpenLayers.Layer.WMS.Untiled( "Luchtfoto's Nederland",
               
"http://intranet.rijkswaterstaat.nl/services/geoservices/basispakket/luchtfoto?",
{layers: 'AAA216', 'format':'image/jpeg', 'transparent':'true'}, {'ratio':1,
isBaseLayer: true} );

            map.addLayers([layer]);            var layer = new
OpenLayers.Layer.WMS.Untiled( "Nationaal Wegen Bestand Wegen wegvakken",
               
"http://intranet.rijkswaterstaat.nl/services/geoservices/basispakket/nationaalwegenbestand?",
{layers: 'AAA70', 'format':'image/gif', 'transparent':'true'}, {'ratio':1,
isBaseLayer: false} );

            map.addLayers([layer]);            var layer = new
OpenLayers.Layer.WMS.Untiled( "Top250namen",
               
"http://intranet.rijkswaterstaat.nl/services/geoservices/basispakket/topografie?",
{layers: 'AAA133', 'format':'image/gif', 'transparent':'true'}, {'ratio':1,
isBaseLayer: false} );

            map.addLayers([layer]);            if (!map.getCenter())
map.zoomToMaxExtent();
            map.addControl(new OpenLayers.Control.LayerSwitcher());
            map.addControl(new OpenLayers.Control.PanZoomBar());
            map.addControl(new OpenLayers.Control.MouseDefaults());
        }

Best regards,
Bart

--
Bart van den Eijnden
OSGIS, Open Source GIS
http://www.osgis.nl


--------- Oorspronkelijk bericht --------
Van: Erik Uzureau <euzuro at gmail.com>
Naar: Bart van den Eijnden OSGIS <bartvde at osgis.nl>
Cc: users at openlayers.org
Onderwerp: Re: [OpenLayers-Users] zooming out when changing base layer
Datum: 11/12/06 09:16

> When you switch between base layers, OpenLayers tries to find the
> nearest approximate
> zoom for the new base layer.
> 
> So what is happening is that when you switch from baselayer A to baselayer
B
> 
> 1) records current extent of map in baselayer A
> 2) switches to base layer B
> 3) calls zoomToExtent() on stored extent from base layer A
> 
> if the resolutions/scales array for your two base layers are not the same,
> this would explain the behaviour.
> 
> Note that with the commercial layers (google, yahoo, etc) we have
specifically
> hard coded the resolutions array so that it will be more consistent with
wms
> layers (due to projection differences).
> 
> On 12/11/06, Bart van den Eijnden (OSGIS) &lt;bartvde at osgis.nl&gt; wrote:
> &gt; Hi list,
> &gt;
> &gt; I have 2 base layers and several overlays, all are WMS Untiled.
> &gt;
> &gt; When I change the base layer, the application zooms out.
> &gt;
> &gt; Is this a bug?
> &gt;
> &gt; Best regards,
> &gt; Bart
> &gt;
> &gt; --
> &gt; Bart van den Eijnden
> &gt; OSGIS, Open Source GIS
> &gt; http://www.osgis.nl
> &gt;
> &gt;
> &gt;
> &gt;
> &gt;
> &gt; _______________________________________________
> &gt; Users mailing list
> &gt; Users at openlayers.org
> &gt; http://openlayers.org/mailman/listinfo/users
> &gt;
> 
>