[OpenLayers-Users] Shifting a layer

[Tyler Erickson]

In my neck of the woods, the current imagery displayed by Google Maps 
and Google Earth imagery are shifted about 10-20m to the east.  You can 
see this when you compare the Google Maps streets data to the satellite 
view (see the following URL).  I have noticed the same thing when 
uploading GPS data that I collected on the local trails that are visible 
in the imagery.

So its possible that is nothing wrong with your WMS layers, but it is 
that the Google Maps imagery in your area is not precisely registered...

Example:
http://maps.google.com/maps?f=q&hl=en&q=ann+arbor,+mi&ie=UTF8&t=h&om=1&ll=42.307451,-83.739821&spn=0.005094,0.009656&z=17

- Tyler


Cranio wrote:
> Yes I do use that projection. I don't know if my WMS layers (that I
> superimpose on Google) are wrong,
> altough they shouldn't (they come from governative sources).
>
> Anyway, the WMS are *not* in S-Mercator, but I think they're reprojected
> correctly.
>
>
> Christopher Schmidt-4 wrote:
>   
>> On Tue, Jan 15, 2008 at 01:42:29AM -0800, Cranio wrote:
>>     
>>> Hi.
>>>
>>> another question. My google layer, when greatly zoomed, appears to be
>>> lightly shifted in
>>> respect to the WMS ones, a shift of about 10-20m in Latitude and 5-10m in
>>> Longitude.
>>>
>>> Is there a way to put an offset somewhere to achieve a perfect
>>> alignment?
>>>       
>> No.
>>
>> Are you using Spherical Mercator? There shouldn't be any shift...
>>
>> Regards,
>> -- 
>> Christopher Schmidt
>> MetaCarta
>> _______________________________________________
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>> Users at openlayers.org
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>>
>>
>>     
>
>   


-- 
Tyler A. Erickson, Ph.D.
Research Scientist
Michigan Tech Research Institute
3600 Green Court, Suite 100
Ann Arbor, MI 48105
tyler.erickson at mtu.edu
www.mtri.org
www.michiganview.org

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