[mapserver-users] Reprojection: Maps not lining up

[Steve Lime]

I'd cc the OpenLayers list too since I think more folks with the Google projection hang
out there...

Steve

>>> On 7/10/2008 at 4:35 PM, in message
<82ba77b80807101435k4f342d99w4359f4c8c5b9188e at mail.gmail.com>, "Matthew Pettis"
<matthew.pettis at gmail.com> wrote:
> (This is a repost, the other one got no responses).
> 
> Hi,
> 
> I am using Openlayers with Mapserver to show a shapefile of roads in MN that
> are in epsg:26915 and allowing users to toggle between that and Google Maps
> (spherical Mercator projection per
> http://spatialreference.org/ref/user/google-projection/).  I use mapserv.exe
> and a .map file to reproject the MN roads into the Google projection, and
> when I toggle between them, the extents *almost* match up.  It appears that
> the MN roads extent covers a slightly larger area than the Google Maps
> extent.
> 
> I don't know if this is an OpenLayers or Mapserver question, but I'm
> thinking it is a Mapserver one.  Can anyone tell me why the extents *almost*
> match up?  I would think that they would either match up almost exactly (or
> at least in a tolerance that I cannot tell by the naked eye), or I would
> have messed up my transformations, and it would be completely out of sync.
> Is it a function of disparities in the data that I cannot fix, or are there
> fine tunings that I can adjust to compensate?
> 
> Thanks,
> Matt