[OSM-dev] Data format for OSM annotation layers

Christopher Schmidt crschmidt at metacarta.com
Sat Nov 25 15:01:02 GMT 2006


On Sat, Nov 25, 2006 at 01:45:10PM +0000, Nick Whitelegg wrote:
> Hello Dan,
> 
> >> Those of you following the Freemap project will know that it includes 
> an
> >> annotation markers layer. It would seem to be a good idea to try and 
> develop
> >> an annotations data format which could be used by OSM mashups in 
> general, and
> >> develop an OpenLayers layer for it so that OSM mashups could easily use 
> it.
> >> Maybe we could just use KML? (I take it that wouldn't violate any 
> Google
> >> copyright issues?)
> 
> >GeoRSS would be perfect for this, wouldn't it? Then you could allow
> >people to subscribe to updates in their area, and it'd be very
> >portable and could be used on many different systems. I'd say KML
> >would be a good addition to a GeoRSS feed, especially as Google
> >Earth/Maps seem to be resisting GeoRSS so far.
> 
> My understanding of GeoRSS is that it is basically a geo-coded RSS format, 
> i.e. it's good for (as you say) alerting people of updates on a map. 
> However it doesn't really seem to be designed for bounding-box retrieval. 
> The sort of app I had in mind involves the user panning an OSM slippy map 
> and markers appearing as you move into new areas. Such an app would 
> require a server which takes a bounding box and returns data of some sort 
> representing the markers within.

Although this is true, WFS Simple is doing exactly this: taking the WFS
format, and changing the output to be encoded in GeoRSS. Starting off
from a script that just includes a bounding box should work ifne, and in
fact, many of the existing GeoRSS server support some kind of location
based query.

Using GeoRSS and adding in a bbox param seems to make perfect sense to
me.

Regards,
-- 
Christopher Schmidt
MetaCarta




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