[Mapserver-users] RE: Shifting points in a projection

[Ed McNierney]

Paul -

I'd suggest trying to find out, from whoever provided you the data, what datum they think was used.  You can fiddle around with datums (NAD27 is next most popular in North America) but if you don't check your sources you can end up fiddling with your data so it's ALL wrong - but looks just fine because you've made it consistently incorrect!

	- Ed

-----Original Message-----
From: Paul Dymecki [mailto:millardymecki at sympatico.ca]
Sent: Wednesday, March 05, 2003 3:19 PM
To: Ed McNierney; MapServer List (E-mail)
Subject: Re: Shifting points in a projection


Thanks Ed,
     I've been given lat/long values which i assumed were NAD83.  Could you
suggest any other datums to try?
thx,
Paul
----- Original Message -----
From: "Ed McNierney" <ed at topozone.com>
To: "Paul Dymecki" <millardymecki at sympatico.ca>; "MapServer List (E-mail)"
<mapserver-users at lists.gis.umn.edu>
Sent: Wednesday, March 05, 2003 3:14 PM
Subject: Shifting points in a projection


Paul -

Can you explain in a little more detail?  Projections by their very nature
shift (i.e. "project") point coordinates.  If you're seeing points show up
in a slightly incorrect place, you've probably got the wrong datum for your
source data.

- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242

-----Original Message-----
From: Paul Dymecki [mailto:millardymecki at sympatico.ca]
Sent: Wednesday, March 05, 2003 2:58 PM
To: MapServer List (E-mail)
Subject: Re: [Mapserver-users] Labels with strange AUTO angles -
fixed,with explanation


Hi,
    I was wondering if anyone would know why points would be shifted down
slightly in a projection?
Paul