[OpenLayers-Users] Feature does not appear in every zoom level

[Christoph Lingg]

Hi Andreas,

thank you for your answer. Unfortunately it didn't work either in IE. Do you know what mechanism is responsible to remove the feature from the map, maybe there is a way to prevent it. If there is no way to achieve this I will have to search another way to stress this region...

Bye,
Christoph

Am 03.08.2010 um 16:58 schrieb Andreas Hocevar:

> Hi,
> 
> does the feature also disappear in Internet Explorer? If not, and if you are not interested in support for older versions of Firefox, Safari and Opera, you could set
> 
> OpenLayers.Renderer.SVG.prototype.MAX_PIXEL = Number.MAX_VALUE;
> 
> before creating your map.
> 
> Regards,
> Andreas.
> 
> On Aug 3, 2010, at 16:28 , Christoph Lingg wrote:
> 
>> Hi list,
>> 
>> I encountered a strange behavior I don't understand: Sometimes I want to cover my whole world map with a dark layer except a distinct region. This is meant to  emphasize a certain region of the world. My approach is creating a polygon with the size of the earth and a hole with the region of interest. Looks like this:
>>> 			var world = new OpenLayers.Geometry.LinearRing([new OpenLayers.Geometry.Point(-20037508.34, -20037508.34), new OpenLayers.Geometry.Point(-20037508.34, 20037508.34), new OpenLayers.Geometry.Point(20037508.34, 20037508.34), new OpenLayers.Geometry.Point(20037508.34, -20037508.34)]);
>>> 			var hole = new OpenLayers.Geometry.LinearRing([new OpenLayers.Geometry.Point(r.x1, r.y1), new OpenLayers.Geometry.Point(r.x1, r.y2), new OpenLayers.Geometry.Point(r.x2, r.y2), new OpenLayers.Geometry.Point(r.x2, r.y1)]);
>>> 			var geo = new OpenLayers.Geometry.Polygon([world, hole]);
>>> 
>>> 			this.ftr = new OpenLayers.Feature.Vector(geo, null, {fill: '#000000'});
>>> 			layer.addFeatures([this.ftr]);
>> Everything is black except the region, perfect! But after zooming in, the feature always disappears after a certain zoom level. Maybe the feature is too big?
>> 
>> Do you have an explanation, a solution or a better approach for this requirement?
>> 
>> Cheers,
>> Christoph
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>> http://openlayers.org/mailman/listinfo/users
> 
> 
> 
> -- 
> Andreas Hocevar
> OpenGeo - http://opengeo.org/
> Expert service straight from the developers.