[GRASS-user] Reprojection from LLC to UTM (various zones)

[Michael Barton]

A UTM projection is not really appropriate for all of North America, which
crosses multiple UTM zones. It is only accurate within a single zone. Try a
different projection that is appropriate for such large areas (e.g., Lambert
Conformal Conic).

Michael


On 8/23/07 2:01 AM, "Miriam E. A." <mespana at ugr.es> wrote:

> 
> Hello everybody,
> 
> I'm triying to reproject a map of north america form llc to utm, but Grass
> reports an error about input map is outside output region.
> 
> I choose zone 16N as center of the map, defining a region as the next, in
> the UTM Location:
> 
> GRASS 6.3.cvs (UTM):~ > g.proj -p
> -PROJ_INFO-------------------------------------------------
> name       : UTM
> datum      : nad27
> towgs84    : -22.000,157.000,176.000
> proj       : utm
> ellps      : clark66
> a          : 6378206.4000000004
> es         : 0.0067686580
> f          : 294.9786982000
> zone       : 16
> -PROJ_UNITS------------------------------------------------
> unit       : meter
> units      : meters
> meters     : 1.0
> 
> g.region n=10000000 s=0 e=10000000 w=0
> 
> to cover the greatest area possible.
> 
> Does grass support regions crossing various zones UTM? And, UTM considers
> north as 0 to avoid negative coords in the north hemisphere, but in GRASS
> south must be 0...
> 
> Maybe i'm very wrong.
> 
> Thanks for your attention and for the help (in this and previous emails
> and irc).
> 
> Miriam

__________________________________________
Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton