[OpenLayers-Users] Proportional Symbol Mapping

[Bjorn Sandvik]

Correct url:
http://thematicmapping.org/experiments/openlayers/propsymbols.html
(Event handler not working)

Bjorn

Bjorn Sandvik wrote:
> Hi Matt,
>
> I'm currently implementing your suggestions. I'm able to size the 
> symbols as a function of the initial zoom level, but I can't figure out 
> how to attach an event handler to the endzoom event. How can I add an 
> event handler which makes a function call?
>
> http://localhost/thematicmapping/experiments/openlayers/propsymbols.html
> (the hover effect still needs some improvements).
>
> Bjorn
> http://blog.thematicmapping.org
>
>
> mpriour wrote:
>   
>> Bjorn
>> The correct way to handle this is to attach an event handler to the endzoom
>> event.
>> This event should manage the size of the symbols so that they are
>> propotionally sized.
>> Choose the zoom level at which the symbol renders at the right proportion,
>> this will be your refernece zoom level. Then size the symbol propotionally
>> the ratio of resolution @ current zoom level / resolution @ reference zoom
>> level. Depending on the event firing order, you may also need to call
>> redraw() on your vector layer.
>> Matt
>>
>> Bjorn Sandvik wrote:
>>   
>>     
>>> Hi,
>>>
>>> I'm currently testing the capabilities of doing thematic mapping with 
>>> OpenLayers.
>>>
>>> This is a proportional symbol map based on GeoJSON encoded data:
>>> http://thematicmapping.org/experiments/openlayers_propsymb.htm
>>>
>>> My question: Is there a way to keep the relative size of the symbols 
>>> when the users zoom in/out?
>>> (symbols should keep their size relative to the size of the countries).
>>>
>>> Bjorn
>>>
>>> http://blog.thematicmapping.org
>>>
>>>
>>>
>>>
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>>>
>>>     
>>>       
>>   
>>     
>
>
>   


-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.