[OpenLayers-Users] IE strategies
Yves Moisan
yves.moisan at boreal-is.com
Mon Jan 12 10:11:20 EST 2009
>
> See the ratio property of the BBOX strategy. You may want to set it to 1
> (the default is 2, which means it will request a bbox twice as large as
> the viewport).
Thank you.
> >
> > http://www.flickr.com/photos/30818159@N05/3182451587/ shows BBOX +
> > Cluster maxFeatures = 200 on the left (results in 101 features) and
> > maxFeatures = 10 on the right (results in 9 features ???). There
> > clearly should be 10 features returned.
>
> This obviously has to do with the ratio property mentioned above:
> maxFeatures applies to the bbox requested from the server, which is
> twice as large as the visible viewport (if using the default ratio of 2).
I see now. One of the features was returned in the portion outside the
viewport and obviously not clustered in the display. I forced ratio to
1 and I now see the expected behaviour. This problem is likely to
manifest itself when maxFeatures is small so it can be tricky.
May I ask why ratio defaults to 2 ? Is it a matter of minimizing calls
to the server for small pan moves ? I believe most users will be
puzzled by not seeing N = maxFeatures in the viewport when they know
there are features.
Thanx again for your explanations.
Yves
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