[OpenLayers-Users] What is the meaning of the result of getLonLatFromPixel ?

[christopher.schmidt at nokia.com]

On Sep 1, 2010, at 3:31 PM, ext Alex Dean wrote:

> 
> On Sep 1, 2010, at 2:20 PM, huit_six wrote:
> 
>> 
>> I tried that sort of conversion :
>>               var point = map.getLonLatFromPixel(position);
>> 		locDisp.innerHTML = (point.lat / 40000000 * 360 ).toFixed(4)+ ', ' +
>> (point.lon / 40065035.535 * 180).toFixed(4);
>> which seem to give results  in the good ranges.
>> But is it really the good way of conversion ? And why the latitude and
>> longitude would be given in meters ? Isn't it weird ? Have I missed
>> something ?
> 
> I couldn't find OpenLayers.Layer.OSM in the API docs, but the  
> coordinates on your sample look like they're in 'spherical mercator',  
> which is common for WMS providers like Google, Yahoo, etc.  http://docs.openlayers.org/library/spherical_mercator.html 
>  says that OSM is indeed spherical mercator.
> 
> So, I think you're getting x & y values in the coordinate system of  
> your base layer.  I think the values are actually a number of meters  
> north & east of 0.  You can translate that to EPSG:4326 (lat/lon)  
> using a function described in this page
> http://dev.openlayers.org/releases/OpenLayers-2.9.1/doc/apidocs/files/OpenLayers/Layer/SphericalMercator-js.html

Also,

  http://docs.openlayers.org/library/spherical_mercator.html

-- Chris

> Also take a look at the re-projection examples on the  
> spherical_mercator.html page I linked to above.
> 
> alex
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