Dear Grass Users,
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.
Cheers
Roy
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Roy Sanderson
Centre for Land Use and Water Resources Research
Porter Building
University of Newcastle
Newcastle upon Tyne
NE1 7RU
United Kingdom
Tel: +44 191 222 7789
Fax: +44 191 222 6563
URL: http://www.cluwrr.ncl.ac.uk
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Hi, Roy
Create a new lat-long Location, and digitize your maps in that Location.
Use v.proj to re-project the lat-long maps to UTM in your other Location.
Hint: both Location should be under the same directory (GRASS
"Database"), though you can always resort to symbolic links if you don't
have enough physical disk space. Happy digitizing,
--
Malcolm D. Williamson - GIS Specialist E-mail: malcolm@cast.uark.edu
Center for Advanced Spatial Technologies Telephone: (501) 575-6159
Ozark Rm. 12 Fax: (501) 575-5218
University of Arkansas
Fayetteville, AR 72701
On Fri, 13 Jun 1997,
R.A.Sanderson wrote:
Dear Grass Users,
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.
Cheers
Roy
----------------------------------------------------------------------------
Roy Sanderson
Centre for Land Use and Water Resources Research
Porter Building
University of Newcastle
Newcastle upon Tyne
NE1 7RU
United Kingdom
Tel: +44 191 222 7789
Fax: +44 191 222 6563
URL: http://www.cluwrr.ncl.ac.uk
----------------------------------------------------------------------------
No-- A location has to contain the same projections, as I understand it.
However, I had good success using r.resample on a ll projection in a ll
location, that covered three UTM zones. I g.copy the file to a temp
mapset. Then with unix commands I moved 'mv' the temp mapset to the UTM
location. Then restarted grass in the UTM location and modified the
cellhd/file into utm coordinates using m.ll2u.
Jason Carey
Snow Hydrology
University of Utah
On Fri, 13 Jun 1997, R.A.Sanderson wrote:
Dear Grass Users,
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.
Cheers
Roy
----------------------------------------------------------------------------
Roy Sanderson
Centre for Land Use and Water Resources Research
Porter Building
University of Newcastle
Newcastle upon Tyne
NE1 7RU
United Kingdom
Tel: +44 191 222 7789
Fax: +44 191 222 6563
URL: http://www.cluwrr.ncl.ac.uk
----------------------------------------------------------------------------