[OSM-dev] Data format for OSM annotation layers

Christopher Schmidt crschmidt at metacarta.com
Sat Nov 25 17:06:12 GMT 2006

On Sat, Nov 25, 2006 at 04:45:49PM +0000, Nick Whitelegg wrote:
> >> OK - looks like GeoRSS it is then.
> >> Doesn't look like it'll be too hard to implement a tiled, bbox-based
> >> GeoRSS layer in OpenLayers... basically a case of taking bits from the
> >> existing (tiled) WFS layer code with the existing (untiled) GeoRSS 
> layer
> >> code.
> >Attach an event that fires Whenever the map stops moving which grabs a
> >feed with that bbox, a-la pubmap.co.uk
> Sounds a good idea - will cut down the number of server requests yet not 
> impact on usability.

I'd recommend taking a look at the WMS untiled layer in version 2.2+ --
it requests a bounding box twice the size of the current display, and
only refreshes when the user moves outside that box. (This saves you
from having to do a refresh on every drag -- if someone only drags 10 or
20% of the viewport, it doesn't grab more data.)

Christopher Schmidt

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