POLYGONS AT INTERNATIONAL DATE TIME BOUNDARY

[Efren Serra]

Gregor,

Do you know which projection handle the date line properly?

-----Original Message-----
From: Gregor Mosheh [mailto:gregor at hostgis.com] 
Sent: Thursday, August 23, 2007 11:36 AM
To: Efren Serra
Cc: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] POLYGONS AT INTERNATIONAL DATE TIME
BOUNDARY


Efren Serra wrote:
> I was wondering how mapserver handles polygons at the international 
> date-time boundary.  Any help would be Appreciated.

Coincidentally, this was asked only last week, and has pertinence to a 
project I'm working on. The answer is: "It doesn't." The entire date 
line issue is that +179 isn't the same as -181, so either:

a) Pick a projection that does handle the date line properly.

b) Pre-mangle your data to get rid of the dateline wrap. Paste the 
Aleutian Islands onto the far east, copy the eastern edge of Russia over 
to the far west from Alaska, so that your data doesn't end at 180/-180

-- 
Gregor Mosheh / Greg Allensworth
System Administrator, HostGIS cartographic development & hosting services
http://www.HostGIS.com/

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