question on projections

fx gamoy fx.gamoy at MAPXPLORE.COM
Fri Nov 12 02:35:26 EST 2004


Hello Franck,
In the same idea,
i ve got a set of data in WGS84. I use those datas on a gps track
application.
Every layers (data and gps data) are processed in latlong WGS84 and
everything works fine.

The only issue is that the map seems to be a little flattened. So i would
like to output it in UTM something.
I am working in whole Europe.
I ve made many try using the projection parameter in the map section
PROJECTION
  "init=epsg:xxxx"
END
but nothing occur...

Any help will be appreciated...
thanks
fx

----- Original Message -----
From: "Frank Warmerdam" <warmerdam at POBOX.COM>
To: <MAPSERVER-USERS at LISTS.UMN.EDU>
Sent: Thursday, November 11, 2004 11:26 PM
Subject: Re: [UMN_MAPSERVER-USERS] question on projections


> Chris wrote:
> > Hi everyone,
> >
> > I'm wondering how I can change from one projection to the other one the
fly,
> > depending on the area of the map I'm in.
> >
> > For example, if I'm using UTM projections, and I pan from one UTM zone
to
> > ther other, how can I switch my output projection let's say from UTM 16
to
> > UTM 17.  It looks like I can only define one output projection in a map
> > file.
>
> Chris,
>
> This would be tricky.  You would likely need to have a bunch of mapscript
> magic to control something like this.  In "normal" use of MapServer, the
> URL will have the requested region to display in the URL but the region is
> in the coordinates of the map.  So you would have to do a whole bunch of
> preprocessing magic in a mapscript script to recognise that a request has
> wandered from one zone into another and transform the requested BBOX as
> well as overriding the mapObj coordinate system.
>
> I personally would encourage you to select a single coordinate system
> appropriate for the whole region you want to work on if at all possible.
> It would save you alot of headaches.
>
> Best regards,
> --
> ---------------------------------------+----------------------------------
----
> I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
>



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