This is correct for the either case (without the extra "+"):

"+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"
There is some limited supported for the 0, 360 convention in PROJ.4 with the
+over argument:

"+proj=longlat +ellps=WGS84 +datum=WGS84 +over +no_defs"

but, that will not perform the required shift in longlat alone, it works
only to disable the "wrap" that would otherwise occur to force the
longitudes back to the -180, 180 convention during a transformation.

See this page for the +over argument in PROJ.4:
http://trac.osgeo.org/proj/wiki/GenParms

Cheers, Mike.

On Sat, Oct 2, 2010 at 4:42 AM, Jonathan Greenberg <greenberg@ucdavis.edu>wrote:

> Folks:
>
> I have two sets of spatialpoints data, one that is in lat long which
> longitude ranging from -180 to 180, and another that ranges from 0 to 360.
>  What are the appropriate proj settings for these two different datasets
> such that one can be properly reprojected to the other?  I have:
>
> "++proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" for the dataset ranging
> -180 to 180 -- is this right?
>
> --j
>
> --
> Jonathan A. Greenberg, PhD
> Assistant Project Scientist
> Center for Spatial Technologies and Remote Sensing (CSTARS)
> Department of Land, Air and Water Resources
> University of California, Davis
> One Shields Avenue
> Davis, CA 95616
> Phone: 415-763-5476
> AIM: jgrn307, MSN: jgrn307@hotmail.com, Gchat: jgrn307
>
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-- 
Michael Sumner
Institute for Marine and Antarctic Studies, University of Tasmania
Hobart, Australia
e-mail: mdsumner@gmail.com

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