In my case, creating the single-tiled map is rather expensive - because the map image is generated "on-the-fly".
Therefore, I want my layer to "anticipate" the map action (zoom, pan), just like the ImageLayer does. I actually had a well working implementation of my map viewer based on ImageLayers, but all the logic (requesting new map etc) happened outside the layer and caused side-effects with other layers. I'm wondering if it would be better to derive my ProprietaryMapLayer from ImageLayer. I could extend it with a getUrlAsync method that fetches the map image url based on the new extent after a map action was performed. Would that work? Franz 2010/8/3 <[email protected]> > > On Aug 3, 2010, at 9:42 AM, ext Franz Buchinger wrote: > > > Hi Bart, > > > > yes, I've set these options. I noticed that these multiple requests only > happen when I set transitionEffect: 'resize'. > > This is basically expected. The transition effect creates multiple tiles, > and since > creating images is generally considered to be 'cheap' in OpenLayers -- > since > images should be served from cache -- we just create more tiles, rather > than > copying existing ones in any way. > > So this is by design; if you don't like the design, you'll need to do some > more coding to fix it :) > > -- Chris > > > I'm using OpenLayers 2.9.1. > > > > Franz > > > > > > > > 2010/8/3 Bart van den Eijnden (OSGIS) <[email protected]> > > Hi Franz, > > > > and have you verified you only have a single tile? > > > > Do you have singleTile: true, ratio: 1 and buffer: 0 in your layer > options? > > > > Best regards, > > Bart > > > > > Hi Bart, > > > > > > I'm almost done with my layer implementation. The only problem: my > > > getURLasync() Method gets triggered far too often (about 3x per > pan/zoom > > > action). > > > > > > How can I make sure that getURLasync is only triggered once per map > > > action? > > > > > > Franz > > > > > > 2010/8/3 Bart van den Eijnden (OSGIS) <[email protected]> > > > > > >> Hi Franz, > > >> > > >> check out OpenLayers.Tile.Image. > > >> > > >> Best regards, > > >> Bart > > >> > > >> > Hi Bart, > > >> > > > >> > thanks for the fast and helpful response! > > >> > > > >> > One question though: which class actually invokes the methods > > >> > OpenLayers.Layer.ArcIMS.getUrl and OpenLayers.Layer.getUrlAsync? > > >> > > > >> > They seem to be overriden methods, but i couldn't find them in > > >> > OpenLayers.Layer.Grid or OpenLayers.Layer.HTTPRequest. > > >> > > > >> > kind regards, > > >> > > > >> > Franz > > >> > > > >> > 2010/8/3 Bart van den Eijnden (OSGIS) <[email protected]> > > >> > > > >> >> Hi, > > >> >> > > >> >> I would advise you to look at OpenLayers.Layer.ArcIMS which uses a > > >> >> similar > > >> >> approach. > > >> >> > > >> >> Best regards, > > >> >> Bart > > >> >> > > >> >> > Hi, > > >> >> > > > >> >> > I'm a frontend developer and was programming a web viewer for a > > >> >> > proprietary, > > >> >> > WMS-like map service. > > >> >> > I discovered Openlayers one month ago and I'm really fascinated > by > > >> its > > >> >> > awesome capabilities, so I decided to integrate our map service > in > > >> >> > OpenLayers. > > >> >> > > > >> >> > Here is a short description how the map service works: > > >> >> > > > >> >> > The client sends an AJAX request containing the current map > bounds, > > >> >> the > > >> >> > map > > >> >> > id and the pixel size of the map. > > >> >> > > > >> >> > > >> > map=22&px=1720&py=833&left=2504400&right=2544000&top=5699500&bottom=5669500&type=0 > > >> >> > > > >> >> > The server responds with the generated map image (url) and the > > >> >> corrected > > >> >> > bounds: > > >> >> > <MapProperties> > > >> >> > <mapLeft>2493227.6110444176</mapLeft> > > >> >> > <mapTop>5699500</mapTop> > > >> >> > <mapRight>2555172.3889555824</mapRight> > > >> >> > <mapBottom>5669500</mapBottom> > > >> >> > <mapType>0</mapType> > > >> >> > <overviewMap>22</overviewMap> > > >> >> > <url> > > >> >> http://localhost/cgmCache/41600065-c3d2-4934-9feb-78a32f6668c8.png > > >> >> > </url> > > >> >> > </MapProperties> > > >> >> > > > >> >> > The maps are always single-tiled. > > >> >> > > > >> >> > My first approach was to write a ProprietaryMapLayer, that > executes > > >> >> the > > >> >> > map > > >> >> > request and creates an ImageLayer with the result url and its > > >> bounds. > > >> >> > When the ImageLayer is moved, a new request is performed, the > > >> current > > >> >> > ImageLayer is destroyed and a new one generated. The > disadvantage: > > >> >> there > > >> >> > are > > >> >> > now 2 layers representing one map, which leads to confusion in > the > > >> >> layer > > >> >> > switcher control. > > >> >> > > > >> >> > I read over the code of Layer.WMS, which inherits from Layer.Grid > > >> and > > >> >> also > > >> >> > makes use of Tile.Image, but it's difficult to derive a solution > > >> from > > >> >> it, > > >> >> > since all the request/response handling is already integrated > into > > >> the > > >> >> > layer. Furthermore, WMS simply responds with tile images, whereas > I > > >> >> have > > >> >> > to > > >> >> > deal with an xml response. > > >> >> > > > >> >> > Any ideas how I could implement my layer? > > >> >> > > > >> >> > kind regards, > > >> >> > > > >> >> > Franz > > >> >> > _______________________________________________ > > >> >> > Users mailing list > > >> >> > [email protected] > > >> >> > http://openlayers.org/mailman/listinfo/users > > >> >> > > > >> >> > > >> >> > > >> >> -- > > >> >> Looking for flexible support on OpenLayers or GeoExt? Please check > > >> out > > >> >> http://www.osgis.nl/support.html > > >> >> > > >> >> Bart van den Eijnden > > >> >> OSGIS > > >> >> [email protected] > > >> >> > > >> >> > > >> > > > >> > > >> > > >> -- > > >> Looking for flexible support on OpenLayers or GeoExt? Please check out > > >> http://www.osgis.nl/support.html > > >> > > >> Bart van den Eijnden > > >> OSGIS > > >> [email protected] > > >> > > >> > > > > > > > > > -- > > Looking for flexible support on OpenLayers or GeoExt? Please check out > > http://www.osgis.nl/support.html > > > > Bart van den Eijnden > > OSGIS > > [email protected] > > > > > > <ATT00001..txt> > >
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