<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">What Tyler suggests, is likely the problem. I have the same issues here in Mexico. The US, IK, etc., are al very well mapped, which is to say, so many third party resources utilize the maps in these regions, that over time Google has corrected their raster/vector sources. About 2 months ago, Google implemented street level maps for Mexico and most of central/south america. First they start with maps.google.com, and then mobile maps, and lastly they populate Google Earth. At this point, they have not yet included Mexico into Google Earth. During this time, the Mexico street level maps have been changed 4 times(that I know of), which is to say I noticed the maps were offline for a period of time(hours, sometimes days), and also noticed position changes across the entire territory, as well as segmented changes. These changes have resulted in sometimes the street-level maps being 4 meters to the east of where satellite images show the roads, and then 3 meters to the south/west, and so on. Over time they continue making improvements, and depending on the community activity of the region, so depends the timeliness and accuracy of the improvements.<div><br class="webkit-block-placeholder"></div><div>I have had to create intentionally inaccurate maps in order to adjust for Google's road positions, so the resulting vector overlay's would be in-line with Google's Satellite street locations. </div><div><br class="webkit-block-placeholder"></div><div>Eric</div><div><br class="webkit-block-placeholder"></div><div><div>On Jan 15, 2008, at 7:31 AM, Tyler Erickson wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"> <div bgcolor="#ffffff" text="#000000"> 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.<br> <br> 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...<br> <br> Example:<br> <a class="moz-txt-link-freetext" href="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">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</a><br> <br> - Tyler<br> <br> <br> Cranio wrote: <blockquote cite="mid:14838962.post@talk.nabble.com" type="cite"> <pre wrap="">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:
</pre> <blockquote type="cite"> <pre wrap="">On Tue, Jan 15, 2008 at 01:42:29AM -0800, Cranio wrote:
</pre> <blockquote type="cite"> <pre wrap="">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?
</pre> </blockquote> <pre wrap="">No.
Are you using Spherical Mercator? There shouldn't be any shift...
Regards,
--
Christopher Schmidt
MetaCarta
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</pre> </blockquote> <pre wrap=""><!----> </pre> </blockquote> <br> <br> <pre class="moz-signature" cols="72">--
Tyler A. Erickson, Ph.D.
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Michigan Tech Research Institute
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