Note that there was a small bug fix to the 900913 transform, I think for high zoom levels, that didn't make it in to 1.5.3. So you may try to download the 1.5.x nightly (http://geo.openplans.org/nightlies/1.5.x/ I think is the url) and see if that fixes your problem.
Note also that the transform I don't believe is in GeoTools yet, it's still just in geoserver. And I'm am pretty sure that the fixed 900913 transform should work for virtual earth, as it's the same projection google uses afaik (the original post that led the OS community to figure this out was VE and GMaps) Chris On Tue, August 21, 2007 10:58 am, Randy George wrote: > > Hi Coop, > > > Hmm... I would have thought the opposite - zoom in bad fit, zoom out > good fit. I will be curious to know if EPSG:900913 solves the issue. > > I see that now the veapi.js doesn't have to be modified (the blog > was from 2006). Did you work out how to fool the tileSourceSpec to point > to a Java servlet? tileSourceSpec.TileSource = > http://someserver:someport/somewebapp/tiles/%4.png";; > > > Randy > > > > -----Original Message----- > From: Brad Cooper [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 21, 2007 8:38 AM > To: Randy George; Geotools-gt2-users@lists.sourceforge.net > Subject: Re: [Geotools-gt2-users] Virtual Earth Transformation Question > > > Thanks for the reply Randy, > That's exactly what I'm experiencing "does not work > well at high zoom values". I've attached two screenshots from a local VE > .html page. The tiles are > getting dynamically generated from a local GeoServer instance and streamed > back to the client using a servlet. As you can see from the screenshot, > the overlay is perfect (we'll looks perfect to the eye) when zoomed in, but > is off when zoomed out (gets worse the more I zoom out). > > Thanks for the tips, I'll try them out and let you > know. > > > > --- Randy George <[EMAIL PROTECTED]> wrote: > > >> Hi Coop, >> >> >> I'm interested in this as well and am planning to >> get to it sometime. Rob Blackwell's blog mentioned that he used EPSG:4326 >> >> "Virtual Earth uses a WGS84 Mercator projection, but >> WMS servers need you to >> specify the projection. In this case we've specified a Coordinate >> Reference >> System (CRS) of EPSG:4326 which is a common >> geographic projection that is equivalent to WGS84." I suspect this does >> not work well at high zoom values. I gather as well that the veapi.js >> needs to be modified. >> >> Chris Holmes mentions this in his GeoServer 1.5.3 >> announcement: >> >> > http://blog.geoserver.org/2007/08/14/geoserver-embraces-the-geoweb/ > >> >> "With a bit of coding from Andrea we're also now >> shipping with support for the map projection used by Virtual Earth and >> Google >> Maps, thanks to SharpGIS >> and Chris Schmidt. So now if you use 900913 as the EPSG code for your >> WMS >> requests our output will be perfectly overlaid on those maps." >> >> 900913 is a custom EPSG created specific to Google >> and VE. You can download the latest version of GeoServer1.5.3 and look at >> the >> > configuration\release\user_projections\epsg.properties >> >> 900913=PROJCS["WGS84 / Simple Mercator", GEOGCS["WGS >> 84", DATUM["WGS_1984", >> SPHEROID["WGS_1984", 6378137.0, 298.257223563]], >> PRIMEM["Greenwich", 0.0], >> UNIT["degree", 0.017453292519943295], >> AXIS["Longitude", EAST], >> AXIS["Latitude", NORTH]], >> PROJECTION["Mercator_1SP_Google"], >> PARAMETER["latitude_of_origin", 0.0], >> PARAMETER["central_meridian", 0.0], >> PARAMETER["scale_factor", 1.0], >> PARAMETER["false_easting", 0.0], >> PARAMETER["false_northing", 0.0], UNIT["m", 1.0], >> AXIS["x", EAST], AXIS["y", >> NORTH], AUTHORITY["EPSG","900913"]] >> >> >> You can use the GeoTools projection code by adding >> this to the EPSG database. Or you could more simply add your own Java >> projection code using the parameters above. >> http://mathworld.wolfram.com/MercatorProjection.html >> >> >> >> Let us know if you succeed in getting the VE WMS >> overlay working >> >> Thanks >> Randy >> >> >> -----Original Message----- >> From: >> [EMAIL PROTECTED] >> > [mailto:[EMAIL PROTECTED] > >> On Behalf Of Brad >> Cooper >> Sent: Tuesday, August 21, 2007 7:01 AM >> To: Geotools-gt2-users@lists.sourceforge.net >> Subject: [Geotools-gt2-users] Virtual Earth >> Transformation Question >> >> >> Hello all, >> I'm new to the GeoTools community and to GIS. I've >> searched the archives and couldn't find any posts/examples on handling >> Virtual Earth Tile >> requests (like this one >> http://viavirtualearth.com/vve/Articles/WMS.ashx). >> Basically I'd like to create a java based proxy >> Servlet that would 1) convert the VE QUAD tile >> requests to bounding box coordinates, 2) transform those coordinates to >> the appropriate ESPG VE reference system, 3) send the appropriate request >> based on the transformed coordinates to a GeoServer WMS, 4) Stream >> the WMS results back to the VE map control. >> >> I understand everything except the transform part. >> Does the community have any sample code to transform >> the Virtual Earth used WGS84 datum to what I guess would be some >> "Mercator projection using a datum >> based on WGS84, BUT modified to be spheric"? >> >> >> Thanks in advance! >> Coop >> >> >> >> >> >> > _________________________________________________________________________ > ___ > >> ________ >> Luggage? GPS? Comic books? >> Check out fitting gifts for grads at Yahoo! Search >> >> > http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz > >> >> > ------------------------------------------------------------------------- > >> This SF.net email is sponsored by: Splunk Inc. >> Still grepping through log files to find problems? >> Stop. >> Now Search log events and configuration files using >> AJAX and a browser. >> Download your FREE copy of Splunk now >> >> http://get.splunk.com/ >> _______________________________________________ >> Geotools-gt2-users mailing list >> Geotools-gt2-users@lists.sourceforge.net >> >> > https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users > >> >> >> > ------------------------------------------------------------------------- > >> This SF.net email is sponsored by: Splunk Inc. >> Still grepping through log files to find problems? >> Stop. >> Now Search log events and configuration files using >> AJAX and a browser. >> Download your FREE copy of Splunk now >> >> http://get.splunk.com/ >> _______________________________________________ >> Geotools-gt2-users mailing list >> Geotools-gt2-users@lists.sourceforge.net >> >> > https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users > >> > > > > > _________________________________________________________________________ > ___ > ________ > Choose the right car based on your needs. Check out Yahoo! Autos new Car > Finder tool. > http://autos.yahoo.com/carfinder/ > > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Geotools-gt2-users mailing list > Geotools-gt2-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users > > > !DSPAM:4005,46cafdc498551804284693! > > > -- Chris Holmes The Open Planning Project http://topp.openplans.org ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
![http://someserver:someport/somewebapp/tiles/%4.png"](http://someserver:someport/somewebapp/tiles/%4.png"){kind=link}