[OpenLayers-Users] Fastest way to create and frequently update ~1000 Features

[Tondo]

Hi

I found JSON a lot faster than XML. If you have access to DB you could get
JSON directly (PostGIS / GeoJSON?). This will reduce server overhead and
should make your app faster (you don't need map server to get features from
DB and create GML that will be send via WFS protocol, you don't need XML to
be parsed and JSON will decrease bandwidth requirements). If you don't have
DB access - or for some reasons you need to use WFS - if you use .NET
platform, you might find  Asynch HTTP Handler
<http://msdn.microsoft.com/en-us/library/ms227433(v=vs.100).aspx>   pretty
fast for parsing GML to JSON especially if you cut off attributes and use
only geometry. But this won't reduce server overhead...

Recelnty I have read Tobias Sauerwein's  bachelor thesis
<http://www.tobias-sauerwein.de/files/Tobias%20Sauerwein%20-%20Evaluation%20of%20HTML5%20for%20its%20Use%20in%20the%20Web%20Mapping%20Client%20OpenLayers.pdf>  
and I found CANVAS being pretty fast for rendering a lot of features. If you
want to click and highlight features you could create one more vector layer
with SVG renderer and simply on click just transfer that feature to
SVG_vector_layer (this shouldn't force CANVAS_vector to redraw).

But this is just a theory I didn't have enogh time to test it...

Tom



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