Line width and projection question

Ed McNierney ed at TOPOZONE.COM
Wed Sep 13 16:35:11 PDT 2006


Chris -

All projections have limitations, and the "geographic" projections have
more limitations than most (e.g. you can't use a scale bar, and you have
a problem at 180W).  You're dealing with a fundamental limitation of
treating latitude/longitude coordinates as if they were Cartesian
coordinates.

Using the PROJ library MapServer supports a wide variety of projections
and if you find one more suitable for your application I'm sure we can
help you figure out how to use it with MapServer.

Your subject line mentions "line width", however, and you didn't mention
it - did you have another question?

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: +1 (978) 251-4242
Fax: +1 (978) 251-1396
ed at topozone.com 

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Christopher Watson
Sent: Tuesday, September 12, 2006 10:41 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: [UMN_MAPSERVER-USERS] Line width and projection question

Hi,

I'm after a fix / work around to what is probably a common problem when
using geographic projections.

I'm using the WGS84 projection (epsg:4326) are there is no 'wrap around'
past the 180E/W meridian, i.e., if i center the map on 180E then the
western half of my global coastline shapefile will not show (with the
inverse is true if i center on 180W).

Tips anyone?

Appreciate your help.

Thanks,
Chris



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