[mapserver-users] Spherical Mercator Projection Problem

[Sergey Kraev]

Thanks! I wasn't aware of that.

Additionally I had to increase layer class maxscale parameter.

Sergey

On Thu, Feb 24, 2011 at 10:33 PM, Jean-François Gigand <
jean-francois at gigand.fr> wrote:

> Hi,
>
> Indeed.
>
> Also note that EPSG:900913 is the same as EPSG:3785 and EPSG:3857.
> These three are the Spherical Mercator projection, which is the right
> one to use for overlays on Google Maps.
>
>
> Jean-François Gigand
>
>
>
>
> 2011/2/24 Fawcett, David (MPCA) <David.Fawcett at state.mn.us>:
> > Sergey,
> >
> >
> >
> > If your data is in epsg:4326 and you want to publish the data as
> epsg:3785,
> > you will need to projection blocks to your layers.
> >
> >
> >
> > Something like:
> >
> >
> >
> >   PROJECTION
> >
> >             "init=epsg:4326"
> >
> >   END
> >
> > The Projection block in the MAP section defines your output projection.
> > Because your data is not in the same projection, you will need to define
> a
> > projection block in each layer section.  Those projection blocks define
> the
> > ‘input’ projection.  They tell MapServer what projection the data exists
> > in.  This allows MapServer (with proj4 support) to re-project your data
> to
> > the output projection.
> >
> >
> >
> > David.
> >
> >
> >
> >
> >
> > From: mapserver-users-bounces at lists.osgeo.org
> > [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Sergey
> Kraev
> > Sent: Wednesday, February 23, 2011 5:01 AM
> > To: mapserver-users at lists.osgeo.org
> > Subject: [mapserver-users] Spherical Mercator Projection Problem
> >
> >
> >
> > Hi,
> >
> >
> >
> > I’m running MS4W v3.0 (including MapServer 5.6.5) on Windows.
> >
> >
> >
> > My data source are PostGIS multipolygon countries’ borders.
> >
> >
> >
> > I have successfully got MapServer to render the world map in WGS84
> > projection using these settings:
> >
> >
> >
> > Request:
> >
> >
> >
> >
> http://127.0.0.1:8080/cgi-bin/mapserv.exe?map=world.map&mode=map&mapsize=256+256&mapext=-180+-90+180+90
> >
> >
> >
> > world.map:
> >
> >
> >
> > MAP
> >
> > EXTENT                   -180 -90 180 90
> >
> >   #EXTENT         -20037508 -20037508 20037508 20037508
> >
> >   SIZE           256 256
> >
> >   IMAGECOLOR     153 179 204
> >
> >   FONTSET        "c:\MS4W\fonts\fonts.list"
> >
> >   RESOLUTION        96
> >
> >   MAXSIZE        5000
> >
> >
> >
> >   PROJECTION
> >
> >             "init=epsg:4326"
> >
> >             #"init=epsg:3785"
> >
> >   END
> >
> > …
> >
> > <layers don’t have PROJECTION sections>
> >
> >
> >
> > I would like MapServer to render the same data into a “Web (spherical)
> > Mercator” projected map (epsg:3785), but I don't know how to modify my
> > request and mapfile in order to get the correct map.
> >
> >
> >
> > With the following settings I just receive a picture without any
> polygons.
> >
> >
> >
> > \ms4w\proj\nad\epsg:
> >
> >
> >
> >                  …
> >
> > <3785> +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 +wktext  +no_defs <>
> >
> > …
> >
> >
> >
> > Request (only mapext is different):
> >
> >
> >
> >
> http://127.0.0.1:8080/cgi-bin/mapserv.exe?map=world.map&mode=map&mapsize=256+256&mapext=-20037508+-20037508+20037508+20037508
> >
> >
> >
> > world.map (only EXTENT and PROJECTION are different):
> >
> >
> >
> > MAP
> >
> >   #EXTENT                -180 -90 180 90
> >
> >   EXTENT         -20037508 -20037508 20037508 20037508
> >
> >   SIZE           256 256
> >
> >   IMAGECOLOR     153 179 204
> >
> >   FONTSET        "c:\MS4W\fonts\fonts.list"
> >
> >   RESOLUTION        96
> >
> >   MAXSIZE        5000
> >
> >
> >
> >   PROJECTION
> >
> >             #"init=epsg:4326"
> >
> >             "init=epsg:3785"
> >
> >   END
> >
> > …
> >
> > <layers don’t have PROJECTION sections>
> >
> >
> >
> > I’m assuming that -20037508 -20037508 20037508 20037508 is correct extent
> > for the whole world map, since Google uses that and they also have
> Mercator
> > projection.
> >
> >
> >
> > Thanks for your help.
> >
> >
> >
> > Sergey
> >
> >
> >
> > _______________________________________________
> > mapserver-users mailing list
> > mapserver-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapserver-users
> >
> >
>
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