Hello everybody. I'm doing some experiments on overlays and I will appreciate comments and ideas.<br><br>My goal is to set up a map with some dynamic information, like traffic events, road conditions etc. The dynamic info should be displayed on an overlay and automatically refreshed even if the user doesn't reload the page.
<br><br>Using the DrawingCanvas of kaMap, the wz_jsgraphics library and some ideas and code circulated on this list I've written a module that fetch a server side generated XML document with the points to draw on the overlay together with rendering directives.
<br>You can view an example in <br><br> <a href="http://sistel.dyndns.info/ka-map/indext.html">http://sistel.dyndns.info/ka-map/indext.html</a><br><br>The script is readable in <a href="http://sistel.dyndns.info/ka-map/kaXmlOverlay.js">
http://sistel.dyndns.info/ka-map/kaXmlOverlay.js</a> and it's tested in Firefox only.<br><br>This is a partial solution to my problem, because it's limited to points, while I would like to display also features as linestrings and polygons. As isn't comfortable doing that with jsgraphics, I've implemented a solution with a wmsLayer that (with some dirty hack) is reloaded periodically.
<br>In the page<br><br> <a href="http://sistel.dyndns.info/ka-map/indexw.html">http://sistel.dyndns.info/ka-map/indexw.html</a><br><br>some streets are highlighted with different colours, and the highlight should change more or less once a minute.
<br><br>I'think this solution is not as good as the previous, because it's slow and produce a very high load on the WMS server.<br>Better solutions could be:<br> a. using jsgraphics to draw 2D features an make them scalable with the map
<br> b. using a server-side script to refresh the cache of a layer and convince the browser to reload only that layer, ignoring the browser-cache<br><br>Have you any ideas about that? Is anyone working on that?<br><br>Bye and sorry for the long posting.
<br><br>Piergiorgio<br><br>