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

[Ivan Grcic]

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