[ka-Map-users] kaXmlOverlay performance problem

Stephen Woodbridge woodbri at swoodbridge.com
Tue May 30 16:16:25 EDT 2006


Have you given any thought to SVG support?

While SVG support in browsers is only in its infancy at the moment, it 
seems that IE 7.0 will have and Firefox already has some level of 
support, but not enough I think for ka-map like application. It also 
seems that Google is moving in that direction so it will be prepared to 
deal with browsers when the support is there.

-Steve W

Pg wrote:
> What you describe is one of the well known issues of kaXmlOverlay.
> An alternative overlay solution, with tiling for big images, has been 
> provided by Lorenzo Becchi & Andrea Cappugi (kaOverlay.js and related 
> files).
> I will release in a short time a new implementatio of kaXmlOverlay using 
> vector graphics (<canvas> or VML) to draw lines and polygons.
> This isn't the definive solution for your problem, but can help.
>  -Pg
> 2006/5/30, Tamas Szekeres <szekerest at gmail.com 
> <mailto:szekerest at gmail.com>>:
>     Hi list,
>     The current implementation of rendering linestrings and polygons use
>     the drawgeom.php (AFAIK).
>     The size of the generated overlay image highly depends on the current
>     scale of the map. When zooming in the image size may be extremely
>     large that increases the download time and the memory usage of the
>     browser.
>     I think this type of the overlay rendering should be reconsidered so
>     as drawgeom should render only a smaller visible segment of the image
>     and a new drawing request should be submitted when the user recenters
>     the map outside of that image area.
>     Any comments would be appreciated.
>     Best Regards,
>     Tamas Szekeres
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