<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><DIV>HI all,</DIV>
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<DIV>I am new to GIS and specifically openlayers.</DIV>
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<DIV>I have a fairly simple WMS app built on openlayers.</DIV>
<DIV>However due to performance I would like to make things seem as if they are performing faster. At the moment we have a tiled layer, and a single none tiled layer. The single layer is loaded first, then we catch a "moveend" then switch the base layer to a tiled one.</DIV>
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<DIV>The initial load is quite quick but then switching to the tiled layer can take some time to satisfy the plethora of requests fired out.</DIV>
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<DIV>What I would like to do is, show the single layer first, then in the back ground immediately fire off the requests for the tiled layer (without displaying it). When they scroll I would like to switch to the tiled layer, which should have hopefully started loading at this point.</DIV>
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<DIV>When they change zoom , i would like to switch back to the single layer (as I think this gives the users something to look at the fastest) then again kick of the tiled layer to load in the background.</DIV>
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<DIV>Is this a feasible and reasonable thing to want to achieve? At the moment I am using a movestart event to change the baselayer hopefully before a zoom. I am comparing the last zoom level with the current one to ascertain whether its been zoomed or not. So,is there anyway to start a tiled layer loading in the background? Is there anyway for a tiled layer to request the visible tiles first? Whats the best way of controlling a switch between a single layer and a tiled layer (we can get quite a large tile for the single layer and dont want to switch immediately)?</DIV>
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<DIV>Sorry for all the questions, it probably just demonstrated my lack of understanding.</DIV>
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<DIV>Any advice greatly appreciated.</DIV>
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<DIV>Thanks</DIV>
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<DIV>Norman</DIV>
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