[mapguide-users] MapGuide OS WMS server

Sat Jul 5 14:51:08 EDT 2008

Hi Maksim,

That's what I needed to know.  The Google projection doesn't use flattening
(I think).  The hack addresses the issue.  

I just wanted to sort out which projection to use before reprojecting
imagery.

Cheers,

Kori Maleski

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Maksim Sestic
Sent: July-05-08 4:02 AM
To: mapguide-users at lists.osgeo.org
Subject: RE: [mapguide-users] MapGuide OS WMS server

Hi Kori,

That's strange, I've been using WGS84 for both raster and vector layers in
Google Earth and everything worked fine. That is - if your actual raster
coverage doesn't get overlayed on top of the poles (WGS84 won't perform well
too north or too south).  There are situations when you need to manually
hack WGS84 transformation parameters, though (see remarks below).

You might try this:

+proj=merc +ellps=sphere +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0
+x_0=0.0 +y_0=0 +k=1.0 +units=m +no_defs

instead of this:

+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0
+k=1.0 +units=m +nadgrids=@null +no_defs 

BTW, EPSG guys are right on this:

"We have reviewed the coordinate reference system used by Microsoft, Google,
etc. and believe that it is technically flawed. We will not devalue the EPSG
dataset by including such inappropriate geodesy and cartography." 

Which they obviously did, and this is not unique case of "technically flawed
PCS" slipping into the EPSG dataset :-) Google/MS have choosen spherical
projection over ellipsoidal one due to speed issues - they didn't foresee
that their datasets will get heavily overlayed with actual, measured data.
End result for EPSG 3785:

Relative to an ellipsoidal development errors of up to 800 metres in
position and 0.7% in scale may arise. Some applications call this WGS 84. It
is not a recognised geodetic system: see WGS 84 / World Mercator (CRS code
3395)   

Regards,

Maksim Sestic

  _____  

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Kori Maleski
Sent: Saturday, July 05, 2008 04:08
To: 'MapGuide Users Mail List'
Subject: RE: [mapguide-users] MapGuide OS WMS server

Hi Maksim,

>From what I understand, vector data will overlay on Google fine via WMS
using WGS84 - EPSG 4326.

I have a number of layers configured this way and it works fine.  But what
about raster imagery?  

Google uses a modified Mercator for its tiles, and I need to overlay some
raster imagery layers.  I need to reproject the raster to the appropriate
map projection for proper display.

If I format images in a modified Mercator, will MapGuide be able to
recognize the projection and will the WMS work?

I added the projections to the files in the nad and data directories for
both the server and web extensions, as well as modified the WMS axd file.  I
can't get it to work.  I get an invalid coordinate system error.  Not sure
if I am doing something wrong or not configuring it correctly.  Hoping
someone else has done this before.

Here is some info on the Google projections:

http://www.sharpgis.net/post/2007/07/26/The-Microsoft-Live-Maps-and-Google-M
aps-projection.aspx

http://www.iter.dk/post/2008/05/SphericalWeb-Mercator-EPSG-code-3785.aspx

Cheers,

Kori Maleski

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Maksim Sestic
Sent: July-03-08 11:55 PM
To: 'MapGuide Users Mail List'
Subject: RE: [mapguide-users] MapGuide OS WMS server

Hi Kori,

Do you have any indicies how is EPSG:3785 different than standard WGS84?
I've been doing coordinate transformation from numerous other CRSes to WGS84
and everything worked fine with Google Earth/Maps. The most important part
of the process is, naturally, getting correct WGS84 transformation
parameters in first place. BTW, decimeter-precision range is out of question
due to GE/GM aerial imagery scale which is, if I recall correctly, 1:5000
(m) at best.

Regards,

Maksim Sestic

  _____  

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Kori Maleski
Sent: Friday, July 04, 2008 02:06
To: MapGuide Users Mail List
Subject: Re: [mapguide-users] MapGuide OS WMS server

Has anyone tried to publish to the new EPSG projection for Google - 3785 -
successfully?

Can the Proj4 library handle custom projections in this manner?

Cheers,

Kori Maleski

On Thu, Jul 3, 2008 at 2:30 PM, Gwenael Bachelot
<gwenael.bachelot at eur.autodesk.com> wrote:

Hi Danas,
I am not sure it is what you are searching for, but I wrote on my blog two
posts on how to publish WMS with MapGuide (using Autodesk MapGuide Studio).
It's in french, but with Google translation (on the left), and screenshots,
I assume it can be useful.
You will find :
- publish WGS 84 WMS service :
http://geospatialfrance.typepad.com/geospatialfrance/2008/06/publier-des-don
.html
- publish with other coordsys :
http://geospatialfrance.typepad.com/geospatialfrance/2008/06/publier-des-d-1
.html

Cordialement,
Gwenael
---------------------------------------
Gwenael Bachelot - Mailto:gwenael.bachelot at autodesk.com
     http://blogs.autodesk.com/geospatialfrance

-----Original Message-----
From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Danas Augutis
Sent: jeudi 3 juillet 2008 15:21
To: MapGuide Users Mail List
Subject: Re: [mapguide-users] MapGuide OS WMS server

I'm not used to mapguide studio, I found 'is published check box, but was
unable to save layer after checking it (save was not active).

Is it somewhere in XML files of layers? I didn't found anything special in
sheboygan layers. Can you send my an example of publishing code, please?

Regards,
D.

On Thursday 03 July 2008 12:52:07 Zac Spitzer wrote:
> there's an is_published flag on the resource header for mapguide
> layers which when set
> exposes them via WMS... mapguide studio makes it easier
>
> if you look at the headers for the sheboygan layers you will see the
> setting in the xml
>
> z
>
> On Thu, Jul 3, 2008 at 7:48 PM, Dumas A <dumas65 at gmail.com> wrote:
> > I'm looking for info about wms services on MGOS. I'm interested to
> > provide some data via WMS.
> >
> > I can see sheboygan example data in ArcCatalog using WMS, but none of my
> > Datasets are in server. Can you tell me where sheboygan example data for
> > WMS is configured? How to configure WMS server for Onw data?
> >
> > Any help appritiated!
> >
> > D.
> >
> > _______________________________________________
> > mapguide-users mailing list
> > mapguide-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapguide-users

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