[OpenLayers-Users] IE strategies

Yves Moisan yves.moisan at boreal-is.com
Thu Jan 8 16:03:54 EST 2009


> What you are describing looks like you do not use the BBOX strategy. 

Andreas,

Here's my vector layer : 

pts_gps = new OpenLayers.Layer.Vector("GeoJSON", {
     strategies: [new OpenLayers.Strategy.BBOX(),new
OpenLayers.Strategy.Cluster()],
     protocol: new OpenLayers.Protocol.HTTP({
     url: "http://myserver:8080/PGTEST4326/all.json",
    format: new OpenLayers.Format.GeoJSON(),
    params:{maxfeatures: 100}
     }),
    format: new OpenLayers.Format.GeoJSON(),
    styleMap: new OpenLayers.StyleMap({
               "default": style,
        "select": {
        fillColor: "#8aeeef",
         strokeColor: "#32a8a9"
         }
    })
});

> Add
> OpenLayers.Strategy.BBOX to your vector layer's strategies array. This
> will also ensure that, once you are zoomed in far enough, all features
> will be visible, even if you set a maxfeatures parameter.

To illustrate what I was saying in the previous email, here's a bunch of
screenshots : 

maxFeatures=  1000 :
http://www.flickr.com/photos/30818159@N05/3180683492/

maxFeatures=  1000, zoomed in :
http://www.flickr.com/photos/30818159@N05/3179845579/

maxFeatures=  5 : http://www.flickr.com/photos/30818159@N05/3180683598/

maxFeatures=  5, zoomed in :
http://www.flickr.com/photos/30818159@N05/3179845687/

The first level of zoom is the same for both maxFeature values.  Zooming
in mean I hit the + sign on the OL control once.  You can see (well
almost) that when I zoom in with maxFeature = 5, i get *3* clusters each
worth 1 feature.  It is clear from the zoomed in example with
maxFeatures = 1000 that there *are* more than 3 features at that zoom
level so I was expecting to see 5 features spread into N <= 5 clusters
so something is wrong there.  If I zoom into the top right portion of my
zoomed out window, I see no feature.  The same rubberband zoom with
maxFeatures = 1000 gives me some features ??

I saw a thread explaining the issue but I don't remember where.  I will
investigate further and report if I find an explanation.

Cheers,

Yves





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