[OpenLayers-Users] WMS not shown below a certain scale

[Till Adams]

Tim,

thanks for your reply. It really pointed us to the right direction -

we were wondering, why OL at one point lost his resolution (  
map.getResolution()  ), then we just added two lines in
VirtualEarth.js at the end of the resolution array (always 50% of the 
value before).
Having no resolution OL could not handle added WMS.

I think this is the same thing as mentioned in ticket 1181 (VE zoom 
levels are weird).

This also fixed other problems we had when zooming to a certain scale.

Thanks for that and best regards, Till



>Hey-
>
>Till Adams wrote:
>  
>
>>Dear list!
>>
>>I have an overlay of MS Ve data with two WMS coming from UMN Mapserver.
>>
>>Although there is no minscale argument defined in the UMN config file, 
>>my open Layers client
>>grays out both WMS when zooming into a certain zoomlevel and does not 
>>show my WMS on the map.
>>The MS VE map is still there.
>>
>>I would expect that the wms is only greyed out, when a certain min or 
>>maxscale is reached.
>>
>>Does anybody have an idea on that?
>>    
>>
>
>Sounds like you are seeing the layer names grayed out in the layer 
>switcher.  This has to do with the minResolution and maxResolution 
>properties of the layer - on the client side.  OpenLayers knows nothing 
>about your mapfile.  So, you'll want to set the minResolution and 
>maxResolution properties of your wms layers to some appropriate level.
>
>A nice way to determine the current map resolution is to get Firefox and 
>install Firebug.  Open the Firebug console and type:
>
>map.getResolution()
>
>Or something different if you have named your map something besides 
>"map."  Figure out what min/maxResolutions you do want for your layers, 
>and then construct them appropriately.  The min/maxResolution properties 
>belong on the options argument to the WMS layer constructor.
>
>That is
>
>var layer = new OpenLayers.Layer.WMS(
>     "Layer Name",
>     url,
>     params,
>     {minResolution: smallNumber, maxResolution: bigNumber}
>);
>
>The units for resolution are map units per pixel.
>
>Note that scale is not well preserved in web mapping.  Your mapfile 
>might assume a client screen resolution of 96 dpi, OpenLayers might 
>assume 72 dpi, and your real monitor resolution (or those of viewers 
>elsewhere in the world) is unknown.  So, stick with resolution (where 
>resolution is defined by map units per pixel).  If you do have to use 
>scale, ensure that your mapfile setting for DPI and your OpenLayers 
>setting for DPI are the same.
>
>Mapfile snip:
>
>     RESOLUTION 96 # dots per inch (default is 72)
>
>OpenLayers config:
>
>     OpenLayers.DOTS_PER_INCH = 96;
>
>Tim
>
>
>
>  
>
>>Regards, Till
>>
>>
>>
>>----------------------------------------------------------
>>terrestris GmbH & Co. KG
>>Irmintrudisstrasse 17
>>53111 Bonn
>>Germany
>>
>>Till Adams
>>Geschäftsführung
>>
>>Tel: +49 (0)228 / 962 899-52
>>Fax: +49 (0)228 / 962 899-57
>>adams at terrestris.de 
>>http://www.terrestris.de
>>Amtsgericht Bonn, HRA 6835
>>---------------------------------------------------------
>>
>>Komplementärin:
>>
>>terrestris Verwaltungs GmbH
>>
>>vertreten durch:
>>Hinrich Paulsen, Till Adams
>>_______________________________________________
>>Users mailing list
>>Users at openlayers.org
>>http://openlayers.org/mailman/listinfo/users
>>
>>!DSPAM:4033,47601215126475219720167!
>>
>>    
>>
>
>_______________________________________________
>Users mailing list
>Users at openlayers.org
>http://openlayers.org/mailman/listinfo/users
>
>  
>


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----------------------------------------------------------
terrestris GmbH & Co. KG
Irmintrudisstrasse 17
53111 Bonn
Germany

Till Adams
Geschäftsführung

Tel: +49 (0)228 / 962 899-52
Fax: +49 (0)228 / 962 899-57
adams at terrestris.de 
http://www.terrestris.de
Amtsgericht Bonn, HRA 6835
---------------------------------------------------------

Komplementärin:

terrestris Verwaltungs GmbH

vertreten durch:
Hinrich Paulsen, Till Adams