[OpenLayers-Dev] OpenLayers 2.11 loading layer data regardless of maxResolution

[Eric Lemoine]

On Thursday, May 3, 2012, Ruben Schoenefeld wrote:

> Hi -
>
> I have been using OpenLayers 2.10 / GeoExt 1.0 / ExtJS 3.2.1 for a while
> now and decided it's time to upgrade to OpenLayers 2.11. Ever since I did,
> I have a problem with my two (mutually exclusive) overlays. Here's how I
> created them:
>
>  l_layer_route = new OpenLayers.Layer.Vector
>    ( "Utah State Routes"
>    , { "strategies":
>        [ new OpenLayers.Strategy.BBOX()
>        ]
>      , "protocol": new OpenLayers.Protocol.WFS(
>        { "version": '&G_WFSVERSION.'
>        , "srsName": 'EPSG:26912'
>        , "url": '&G_WFSMAP.'
>        , "featureType": '&G_WFS_ROUTE.'
>        , "featureNS": '&G_GEOSERV_NAMESPACE.'
>        , "geometryName": 'GEOM'
>        })
>      , "visibility": true
>      , "styleMap": l_style_route
>      , "minResolution": 0.298582153289307
>      , "maxResolution": 20
>      , "units": 'm'
>      , "alwaysInRange": false
>      }
>    );
>
>  l_layer_centerline = new OpenLayers.Layer.Vector
>    ( "Local Street Centerlines"
>    , { "strategies":
>        [ new OpenLayers.Strategy.BBOX()
>        ]
>      , "protocol": new OpenLayers.Protocol.WFS(
>        { "version": '&G_WFSVERSION.'
>        , "srsName": 'EPSG:26912'
>        , "url": '&G_WFSMAP.'
>        , "featureType": '&G_WFS_CENTERLINE.'
>        , "featureNS": '&G_GEOSERV_NAMESPACE.'
>        , "geometryName": 'GEOM'
>        })
>      , "visibility": false
>      , "styleMap": l_style_centerline
>      , "minResolution": 0.298582153289307
>      , "maxResolution": 4
>      , "units": 'm'
>      , "alwaysInRange": false
>      }
>    );
>
> The locations in the WFS protocol entries are populated when the page is
> run. The routes layer contains fewer records "per area" than the street
> centerline layer, so it should be okay to display it at 20 m / pixel. The
> centerline layer should be displayed at 4 m / pixel. I've got the following
> resolutions on the map, which come from the first base map that I add:
> [4891.96999883583, 2445.98499994708, 1222.99250010583, 611.496250052917,
> 305.748124894166, 152.8740625, 76.4370312632292, 38.2185156316146,
> 19.1092578131615, 9.55462890525781, 4.77731445262891, 2.38865722657904,
> 1.19432861315723, 0.597164306578613, 0.298582153289307]
>
> When I initially load the map, the resolution is 1222.99250010583 m /
> pixel, to display the whole state of Utah. The extent of the map on my
> screen is -296596.91381471, 3855627.9299551, 1199122.9138147,
> 4892725.5700449.
>
> All the layers (base maps and overlays) use the EPSG:26912 projection.
>
> So from that, as expected, neither the routes or centerline layers are
> loaded, which is great and as I expect it. As you can see in the layer
> definition for the routes layer (the first of the two), its visibility is
> "true" when the layer is created. Yesterday, more or less on accident, I
> used the layer switcher to switch from the routes layer to the centerline
> layer, which happens by executing this:
> l_layer_route.setVisibility(false);
> l_layer_centerline.setVisiblity(true);
>
> This worked fine in OpenLayers 2.10, but since I switched to 2.11, what
> happens now (while displaying the whole state) is that it first loads all
> the data for the routes layer of that huge extent, which takes forever and
> is multiple MB of data and then it loads all the data for the centerline
> layer, which is too much for Firefox and I get it to crash.



Woo. That's indeed unexpected and abnormal.




>
> So my questions:
> 1) Why would OpenLayers want to load the data when maxResolution on the
> layers clearly tells it that it shouldn't?



It should not.



> 2) Why would OpenLayers want to load the data for the routes layer when I
> am setting its visibility to false but it didn't care to do that when I
> initially loaded the page (and shouldn't have)?



It should not.



3) What am I doing wrong?
>
> Because I first experienced this problem with OpenLayers 2.11, I switched
> back to 2.10 just to see if it happens there, and it didn't. I also
> upgraded GeoExt to 1.1 now and that doesn't make a difference. Also,
> initially, I didn't have the minResolution set, but only maxResolution. But
> I added it now, but that doesn't make a difference.
>
> Please let me know if further information is needed.



I'd be curious to know if the same issues exist with 2.12-rc2. And it'd be
great to come up with a minimal example demonstrating the problem.

Cheers,


-- 
Eric Lemoine

Camptocamp France SAS
Savoie Technolac, BP 352
73377 Le Bourget du Lac, Cedex

Tel : 00 33 4 79 44 44 96
Mail : eric.lemoine at camptocamp.com
http://www.camptocamp.com
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