On 01/17/2011 06:45 PM, Roy Hyunjin Han wrote:
If I set my OpenLayers.Layer.Vector projection to 4326 and my map
projection to 3857, I get the following sample.
bbox=-974.00597306406,-179.26033291361,825.99402686406,179.62415110059
What are the units here?
If I set my OpenLayers.Layer.Vector projection to 3857 and my map
projection to 3857, I get the following sample.
bbox=-108425848.93601,-75336276.762761,91949234.455994,85276876.018639
What are the units here?
However, in Polymaps, I get the following sample, which I am assuming
is in latitude, longitude, latitude, longitude format and decimal
degree units.
bbox=-85,0,0,180
>> bounds = new
OpenLayers.Bounds(-974.00597306406,-179.26033291361,825.99402686406,179.62415110059)
>> projMap = mapOL.getProjectionObject()
>> projLayer = new OpenLayers.Projection("EPSG:4326");
>> bounds.transform(projLayer, projMap)
left-bottom=(-108425848.93601,NaN) right-top=(91949234.455993,NaN) {
left=-108425848.93601, bottom=NaN, more...}
Hmm.
According to the following code in OpenLayers/Strategy/BBox.js, it
appears that BBox expresses the bounds in the same projection as the
layer. However, the numbers look much more like meters than degrees. I
know the map projection is in meters, but the layer projection should be
in degrees.
update: function(options) {
var mapBounds = this.getMapBounds();
if ((options && options.force) || this.invalidBounds(mapBounds)) {
this.calculateBounds(mapBounds);
this.resolution = this.layer.map.getResolution();
this.triggerRead();
}
},
/**
* Method: getMapBounds
* Get the map bounds expressed in the same projection as this layer.
*
* Returns:
* {<OpenLayers.Bounds>} Map bounds in the projection of the layer.
*/
getMapBounds: function() {
var bounds = this.layer.map.getExtent();
if(!this.layer.projection.equals(this.layer.map.getProjectionObject())) {
bounds = bounds.clone().transform(
this.layer.map.getProjectionObject(), this.layer.projection
);
}
return bounds;
},
Still confused.
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