<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial,helvetica,sans-serif;font-size:10pt"><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;">I've used the MapServer Untiled Layer-type and have had it use the blank-image url as the URL to mapserver. I've found this useful for doing some debugging as it always gives me a nice clean reference to the mapsize and mapext in the URL. :-)<br><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">----- Original Message ----<br>From: Tim Schaub <tschaub@openplans.org><br>To: dev@openlayers.org<br>Sent: Monday, December 10, 2007 3:43:50 PM<br>Subject: Re: [OpenLayers-Dev] Null basemap?<br><br>
Jeff Yutzler wrote:<br>> In the past we've always been told that you must have a basemap to
use <br>> OpenLayers. "So many things are keyed off of the base map, it must
be <br>> there or things just won't work." However, I find this to be an
awkward <br>> constraint, particularly if you have an OGC context that you are <br>> loading. OGC contexts have no knowledge of the concept of base map -
<br>> everything is just a layer and the "basemap" is naturally the bottom <br>> layer of the context. To get around this, I developed a dummy "Null"
<br>> basemap class that always returns blank.gif. Is this an acceptable <br>> solution to the problem? If so, would this be a worthwhile
ticket/patch <br>> to provide?<br><br>I agree that it is an awkward constraint. My issue is more with the <br>coupling of map.baseLayer and the layer.isBaseLayer property.<br><br>Ideally, we'd have a map.displaySRS or something. Without this
property <br>set however, it is nice to have the map draw projection related <br>information from somewhere. The map.baseLayer currently serves that <br>purpose. The weird part (in my mind) is also having a
layer.isBaseLayer <br>property. What we really want to know is "can this layer be displayed <br>in a different SRS?" The layer.isBaseLayer property sort of means "no"
<br>in response to this question - but it is a bit too broad.<br><br>My workarounds have been about making layers[0] act as a base layer.
If <br>you want a dummy layer to serve this purpose, there are a bunch of <br>options without patching the trunk. An image layer with displayInLayer
<br>false sounds like an easy one to me.<br><br>I do like the idea of working towards a more flexible handling of the <br>base layer concept.<br><br>Tim<br><br>> <br>> <br>> !DSPAM:4033,475da7b1165291961014482!<br>> <br>> _______________________________________________<br>> Dev mailing list<br>> <a ymailto="mailto:Dev@openlayers.org" href="mailto:Dev@openlayers.org">Dev@openlayers.org</a><br>> <a href="http://openlayers.org/mailman/listinfo/dev" target="_blank">http://openlayers.org/mailman/listinfo/dev</a><br>> <br>> <br>> !DSPAM:4033,475da7b1165291961014482!<br><br>_______________________________________________<br>Dev mailing list<br><a ymailto="mailto:Dev@openlayers.org" href="mailto:Dev@openlayers.org">Dev@openlayers.org</a><br><a href="http://openlayers.org/mailman/listinfo/dev" target="_blank">http://openlayers.org/mailman/listinfo/dev</a><br></div><br></div></div><br>
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