On Nov 8, 2010, at 3:50 PM, ext karsten vennemann wrote: > Hi all, > > I bumped into a big issue with being able to use OpenLayers for our project > in regards on how the client wanted to use their web maps. > > They are using tile based services such as OSM an Google as base layers, thus > also using spherical merc. for the map projection of the other map layers and > the map display. I had noticed for a while that OpenLayers somehow magically > calculates the map extent and zoom level when a zoom action is performed but > that there is a restriction on which exact map extent you can zoom to - when > using tile based layers with fixed zoom levels. Now that might work for many > applications use cases but in the case of very tiny labels (and very many of > those) this is a big issue (and maybe show stopper for us) namely that one > can't zoom into any scale. The desired functionality is to zoom to a > rectangle (rectangle zoom or shift+zoom action) and that the selected > rectangle then will become about the map extent (plus /minus). I understand > that works only if one is not using tile base layers with their fixed zoom > scales...whereas with vectors or on the fly rendered layers this works really > well. The reason the clients absolutely needs that is to maximize their tiny > labels for editing purposes and at the same time being able to exactly define > a map extent they are working on. > > So one solution scenario I thought off would be to abandon the tiled layers > altogether and use "on the fly rendering" of our own background layers. > One question I have is the following: could we work around this functional > behavior in OpenLayers (the tiled base layers stopping us to zoom to any map > extent) when I add a dummy base layer (with no or minimal base map rendered > on the fly but using the single tile option? Would that allow us to any scale > and map extent. My guess is that it would not because the other base layers > are still in the map document even though turned off ?
You can use a baseLayer with fixedZoomLevels: false (though that might be a map option, rather than a layer option) which lets you zoom to arbitrary levels. This option won't work with layers like OSM/Google, but will work with WMS + (I believe) vector layers. -- Chris > Is there any options I could turn on in OL or on the map and layers that > dis/enables this behavior (even if the base map layers would become really > pixely that would be fine but we would nee to disable some of the magic > OpenLayers map extent calculations ? > Any other advice we could make this work somehow ? > > Thanks > Karsten > Karsten Vennemann > > Terra GIS LTD > Seattle, WA 98112 > USA > www.terragis.net > > <ATT00001..txt> _______________________________________________ Users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/openlayers-users
