[ka-Map-users] Overlays with dynamic information

Sige sigenz at yahoo.co.nz
Tue Feb 21 19:17:00 EST 2006

Hi Pg,

I tested the features on your website as well as on
the source code from cvs. seems it works fine with
firebox. with IE, it works when the page is first
loaded, when the page is refreshed, the dynamic
features disapear. i think this might have something
to with client side cache, but not sure exactly where
it is.



On 30-Dec-05, at 5:52 AM, Pg wrote:

> Hello everybody. I'm doing some experiments on
overlays and I will  
> appreciate comments and ideas.
> 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.
> 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
> You can view an example in
>    http://sistel.dyndns.info/ka-map/indext.html
> The script is readable in
> kaXmlOverlay.js and it's tested in Firefox only.

it also works in Safari :)  ... any idea if it works
in IE yet?

> 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.
> In the page
>    http://sistel.dyndns.info/ka-map/indexw.html
> some streets are highlighted with different colours,
and the  
> highlight should change more or less once a minute.
> 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.
> Better solutions could be:
>   a. using jsgraphics to draw 2D features an make
them scalable  
> with the map
>   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
> Have you any ideas about that? Is anyone working on

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