[OpenLayers-Users] Cluster Strategy and Google Layer

GordonHo llian at gmx.net
Mon Nov 17 10:53:13 EST 2008


hi,

i had a similiar problem though got it solved.
here the configuration i use:

		var options = {
	                projection: new OpenLayers.Projection("EPSG:900913"),
	                displayProjection: new OpenLayers.Projection("EPSG:4326"),
	                units: "m",
					panMethod: OpenLayers.Easing.Quad.easeOut,
	                numZoomLevels: 12,
	                minZoomLevel: 1,
	                maxResolution: 156543.0339,
	                maxExtent: new OpenLayers.Bounds(-20037508, -20037508,
	                                                 20037508, 20037508.34),
			    controls:[
						    new OpenLayers.Control.Navigation({'zoomWheelEnabled': false}),
						    new OpenLayers.Control.MousePosition(),
						    new OpenLayers.Control.PanZoomBar({zoomStopHeight:12,
zoomWorldIcon:true}),
					    ]
	            };
	            
	var layerPhy = new OpenLayers.Layer.Google("Terrain", {type:G_PHYSICAL_MAP,
wrapDateLine:true, 'sphericalMercator': true});


	var markers = new OpenLayers.Layer.Vector("Markers", {
                    strategies: [
                        bbox ,
                        new OpenLayers.Strategy.Cluster()
                    ],
                    protocol: new OpenLayers.Protocol.HTTP({
                        url: "/AJAX/GeoData.php",
                        params: {
                        },
                        format: new OpenLayers.Format.Text({
							internalProjection: map.getProjectionObject(),
							externalProjection: map.displayProjection
							})	
                    }),
                    styleMap: new OpenLayers.StyleMap({
                        "default": style,
                        "select": {
                            fillColor: "#808080",
                            strokeColor: "#000000"
                        }
                    })
                });


important were:
 - displayprojection and projection in the map constructor
 - spheciralmercator on google map
 - internal / external projection on the format

hope this helps... 

cheers, gordon


mippon wrote:
> 
> 
> Have a look at this thread, 
> 
> http://www.nabble.com/forum/ViewPost.jtp?post=20371907&framed=y
> 
> 
> Salvaro wrote:
>> 
>> 
>> Hey,
>> 
>> I just added in Map Options the projection EPSG:900913.
>> The Google layer is with the same parameters, and Vector Layer in options
>> only receive an array with Fixed and Cluster Strategies.
>> 
>> MapOptions: numZoomLeves=19, projection=EPSG:900913,
>> displayProjection=EPSG:4326 and the controls.
>> Vector Layer: strategies=a strategies array.
>> Google: projection=EPSG:900913, type=GMAPS, Bounds=-20037508.34,
>> -20037508.34,20037508.34, 20037508.34,
>> maxResolution=156543.0339F,sphericalMercator=true, units=m.
>> 
>> The problem only happens with Google Layer (as you can see above), in WMS
>> (EPSG:4326) it works well.
>> 
>> Have no idea about what is happening.
>> 
>> Thanks, Eric!
>> 
>> 
>> Eric Lemoine wrote:
>>> 
>>> Hi Salvaro. Please show us your new code. Eric
>>> 
>>> 2008/11/3, Salvaro <asufsc at gmail.com>:
>>>>
>>>> Hi Eric, thanks for your answer!
>>>>
>>>> I set in the map this projection, but the problem still continues.
>>>> If the points are in the correct coordinates (reprojection), the
>>>> cluster
>>>> strategy is ignored by the layer.
>>>> Else if the points are in the incorrect coordinates the cluster
>>>> aparently
>>>> works, but obviously all the points are in the center of the map.
>>>>
>>>> I tried much things, but really have no idea about what it can be =/.
>>>>
>>>> Thanks!
>>>>
>>>> Using WMS in EPSG:4326 all works well.
>>>>
>>>>
>>>> Eric Lemoine wrote:
>>>>>
>>>>> Hi. The EPSG:900913 projection should be set in the map options. In
>>>>> this way your vector layer is also a 900913-projected layer. If your
>>>>> vector points are expressed in 4326 you have to have them re-projected
>>>>> before the're added to the layer. Eric
>>>>>
>>>>> 2008/10/31, Salvaro <asufsc at gmail.com>:
>>>>>>
>>>>>> I'm using a Vector Layer with Cluster Strategy (and Fixed) overlaying
>>>>>> a
>>>>>> WMS
>>>>>> (EPSG:4326) and a Google Layer (EPSG:900913).
>>>>>>
>>>>>> In the WMS layer the strategy works perfectly. But in Google Layer,
>>>>>> the
>>>>>> layer apparently ignores the Strategy.
>>>>>>
>>>>>> Testing I saw a "strange" thing, when I use the points in EPSG:4326
>>>>>> coordinates in the Google Layer and all points are in the centre of
>>>>>> the
>>>>>> map,
>>>>>> looking the opacity is possible to see the points being "clustered".
>>>>>> But
>>>>>> when I try to reproject them or just set different coordinates of the
>>>>>> google
>>>>>> projection, the layer ignores the cluster.
>>>>>>
>>>>>> The points with correct projection:
>>>>>> http://img225.imageshack.us/my.php?image=correctprojectionyx8.jpg
>>>>>>
>>>>>> And with the incorrect projection:
>>>>>> http://img404.imageshack.us/my.php?image=wrongprojectiontk6.jpg
>>>>>> http://img505.imageshack.us/my.php?image=wrongprojection2ty8.jpg
>>>>>>
>>>>>> I'm using in the Map these attributes: numZoomLevels=19,
>>>>>> displayProjection=EPSG:4326 and the controls.
>>>>>> In the layer: type=GMAPS, projection=EPSG:900913,
>>>>>> maxExtent=-20037508.34,
>>>>>> -20037508.34, 	20037508.34, 20037508.34, units=m,
>>>>>> maxResolution=156543.0339F
>>>>>> and sphericalMercator=true.
>>>>>>
>>>>>> The points are being added using addFeatures.
>>>>>>
>>>>>>
>>>>>> Anyone have an idea about what it can be and how can I do the cluster
>>>>>> works
>>>>>> with the Google Layer?
>>>>>>
>>>>>> Thanks!
>>>>>> --
>>>>>> View this message in context:
>>>>>> http://n2.nabble.com/Cluster-Strategy-and-Google-Layer-tp1402961p1402961.html
>>>>>> Sent from the OpenLayers Users mailing list archive at Nabble.com.
>>>>>>
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>>>>
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