Map Projections

[Malcolm Williamson]

Jill,
I don't believe that the datum transformation option ever made it into 
the CERL release of GRASS (someone correct me if I'm mistaken). Can you 
supply the source for that? Thanks,
	-Malcolm

On Fri, 13 Jun 1997, Jill Schuler wrote:

> >From: "R.A.Sanderson" <R.A.Sanderson at newcastle.ac.uk>
> 
> >Is there a simple way of using two map projections simultaneously in GRASS?
> > I have a GRASS location in UTM, but need to add new maps by digitising
> >from base maps stored as latitude-longitude.  The v.digit command only
> >seems able to cope with digitising using the same projection as the
> >original location (in this case UTM). I could resort to using Arc/Info for
> >digitising, then PROJECT/TRANSFORM into UTM before exporting to GRASS, but
> >I'd prefer to carry out the whole operation in GRASS if possible.
> 
> Yes, use the v.proj command to project your utm location to lat/long
> 
> Usage:
>  v.proj map=name [out=name] inloc=name [dbase=name] [set=name]
>  
> Parameters:
>     map   input vector file name
>     out   output vector file name
>   inloc   Location containing INput vector map
>   dbase   Database containing INput location
>     set   mapset containing INput vector map
> 
> You can also use v.proj to shift your datum from nad27 to nad83.  Just 
> create a file called DATUM_INFO under your PERMANENT mapset.  The file
> contains 2 lines:
> 
> datum: nad27  or nad83
> region: conus
> 
> v.proj is a contributed command under the src.contrib/SCS/mapdev/v.proj 
> directory.
> 
> Jill
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> 
> Jill R. Schuler
> USDA 
> Natural Resource Conservation Service
> 2627 Redwing, Suite 120
> Ft. Collins, Co 80526                     FAX: (970) 282-1930
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> e-mail: jschuler at itc.nrcs.usda.gov        Phone: (970) 282-2418
>