[OpenLayers-Dev] Grid Strategy - feedback and few questions

[Ivan Grcic]

Eric, i guess that you need to include this to grid strategy also:

http://trac.openlayers.org/ticket/1840

Cheers,

On Mon, Feb 23, 2009 at 12:14 PM, Ivan Grcic <ivan.grcic at geofoto.hr> wrote:
> Hi all,
>
> well i guess this primarly goes to Eric but anyone can jump in :)
>
> Ive just tried gridStrategy from vector-behavior
> http://dev.openlayers.org/sandbox/vector-behavior/ and im pretty happy
> how it works.
> So i just want to drop few lines while impressions are still fresh. i
> know its still in develop. so maybe thats the answear to some of my
> questions ;)
>
> First improvment one can see beetwen strategies Grid & BBOX is the
> similar one to WMS & WMS.Untiled. When you drag the map, features dont
> dissapear but only new ones load. Very very nice!
>
> But when you observe XHR traffic, there are much more requests, cuz it
> splits big request to 256x256 tiled requests. First thing i did is to
> set option tileSize: new OpenLayers.Size(512,512) and I got satisfing
> number of 4-8 request per map move. As i used only points features i
> put options safe: false.
>
> 1)First question, setting tile size different then map is perfectly
> ok, right? Doesnt affect anythign else then Grid strategy?
>
> Few words about buffer option:
> Setting buffer to lets say 2, i could see that there are much more
> requests, and inside strategy-grid-grid object i can see that there
> are many more objects (tiles).
> But when i move my map just for 20px, new requests are being issued
>
> 2) Shouldnt I have at least 512px (tile size) before new requests are made?
>
> And one more question, featuresadded event is triggered for every tile
> loaded, thus it makes it little bit harder to see when all the
> features are loaded. What would be the right way to do it?
>
> I just saw that inside Grid.js
> /* FIXME addTileMonitoringHooks: function(tile) {
>
> that should answear my question. Any tickets for that issue maybe?
>
> That would be all from me, for now :)
> Thank you
>
> PS
> http://dev.openlayers.org/sandbox/vector-behavior/examples/strategy-grid.html
> gives error:
> this.format is null
> [Break on this error] return this.format.read(doc);
>
> ...and i also have one bug, but ill just write it aside, and ask it
> later to keep email smaller :)
>
> Cheers
>
>
> --
> Ivan Grcic
>



-- 
Ivan Grcic