[OpenLayers-Users] Large Vector Layer

[Christopher Schmidt]

On Fri, Aug 17, 2007 at 03:02:25PM +0200, Eric Lemoine wrote:
> Hi Scott,
> 
> Answering two of your questions below:
> 
> On 8/16/07, Scott Davis <scott at davisworld.org> wrote:
> >
> > [...]
> >
> > Thanks for taking the time to respond, Gregor. I really appreciate
> > it. However my questions remain:
> > Does WFS sound like the right solution -- given a 10k datalayer than
> > needs hover capabilities -- for out of the box OpenLayers 2.4 and
> > GeoServer 1.6.nightly?
> > Does GeoRSS currently get constrained to the map bbox like WFS in
> > OpenLayers 2.4?
> 
> I've just looked into the code, and it seems to me that the GeoRSS
> Layer doesn't do what you want - it does not constrain its request to
> the map bbox. Hopefully, someone can confirm here...

This is true. The way to do this going forward is probably to
finish/create the GeoRSS 'read' support for the GeoRSS format class:
this will allow one to simply pass {'format':OpenLayers.Format.GeoRSS}
to the WFS layer, and it will parse the data as GeoRSS instead of GML.
(This works today with KML, though I'll admit the KML support isn't that
great to begin with.)

> > Any thoughts on the differences/benefits/drawbacks of an old Marker
> > layer vs. a new Vector layer?
> 
> With the new Vector Layer, not only can you display points, but also
> lines, polygons, etc. And if you use the current SVN code, you can
> also display markers in a Vector Layer, using the externalGraphic
> property. So Basically, I don't see any advantages of using the old
> Markers Layer.

It works in Safari 1/2. It supports offsets, so a marker can be
positioned relative to a point (so the marker points accurately at the
point). It makes registering click events to cause popups or similar
easier. It's longer used, and therefore better tested. 

Again going forward, it's likely that if you have lots of vector data,
that the vector layers will be what you want. However, if you just want
to stick something on the map and have clickable popups -- the default
'mashup' use case -- then you probably want to stick with markers for
the time being.

> > Does OpenLayers 2.5 RC 1 bring anything to the party that would
> > significantly ease my pain?

2.5 RC1 doesn't exist yet, for the record, but the answer either way is
"No".

Regards,
-- 
Christopher Schmidt
MetaCarta