[GRASSLIST:5678] Re: [STATSGRASS] Using GRASS/R interface with an xy location &

Ok, the issues all seem to derive from the region settings created by GRASS 5.7. In order to work in this location with GRASS 5.4, I had to modify the DEFAULT_WIND file. Just had to remove the extra lines 5.7 uses to get the following:

GRASS 5.4.0 > cat DEFAULT_WIND
proj: 0
zone: 0
north: 100
south: 0
east: 100
west: 0
cols: 100
rows: 100
e-w resol: 1
n-s resol: 1

After modifying DEFAULT_WIND, I could connect GRASS 5.7 and R without any problems. I don't know (yet!) if changing the default region settings will have any implications for working in GRASS 5.7.

FYI -- I attached a 5.7/R session prior to modifying DEFAULT_WIND, including the 'reverse(G)' error (below). Maybe it will be of use for updating the GRASS/R interface.

> library(GRASS)
GRASS environment variables in: /tmp/grass6-steve-3644/gisrc
> G<-gmeta()
Error in gmeta() : region for current mapset is invalid
line 11: <top: 100>
run "g.region"

> G<-gmeta(interp=TRUE)
> summary(G)
Data from GRASS 5.0 LOCATION NL1 with 100 columns and 100 rows;
projection: 0 (x,y); zone: 0
The west-east range is: 0, 100,
and the south-north: 0, 100;
West-east cell sizes are 1 units,
and south-north 1 units.

> rb1<-rast.get(G, rlist=c("rb1"),interp=T)
> plot(G, rb1$rb1)
Error in reverse(G) : cannot allocate vector of length 1086556160

---
Steven T. Stoddard

Program in Ecology, Evolution and Conservation Biology
University of Illinois at Urbana-Champaign

(217) 333-2235
302 Shelford Vivarium
606 E. Healy Ave
Champaign, IL 61820
http://www.life.uiuc.edu/~sstoddar

On Feb 8, 2005, at 11:18 AM, Roger Bivand wrote:

On Tue, 8 Feb 2005, Steven T.Stoddard wrote:

Ok. The work-around I can grow accustomed to, or I might fall back on
GRASS5.4 if that works.

I wonder if another problem that cropped up is somehow related to the
first. Using interp=TRUE I managed to import a raster map to R. But
when trying to plot it, I get the following:

plot(G,tt$rb1)

Error in reverse(G) : cannot allocate vector of length 1086556160

What does summary(G) say? It sounds as though the numbers of rows and/or
columns have the wrong values.

Over 1G cells is a bit extreme?

Roger

???

Thanks for the help,
Steve

---
Steven T. Stoddard

Program in Ecology, Evolution and Conservation Biology
University of Illinois at Urbana-Champaign

(217) 333-2235
302 Shelford Vivarium
606 E. Healy Ave
Champaign, IL 61820
http://www.life.uiuc.edu/~sstoddar

On Feb 8, 2005, at 10:58 AM, Roger Bivand wrote:

On Tue, 8 Feb 2005, Steven T.Stoddard wrote:

I am using GRASS 5.7 and R 2.0 for OS X. I have a simple xy location
I
am doing some theoretical work with and would like to import maps into
R using the interface in order to do analyses. Yet when I attempt to
do this, I get the following error:

G<-gmeta()

Error in gmeta() : region for current mapset is invalid
line 11: <top: 100>
run "g.region"

I traced the problem to the compiled C program that is called from the
gmeta R function (i.e. > .C("gmeta") gives me the same error). I
haven't been able to locate the source code on my volume.

If I use gmeta(interp = TRUE) there is no problem, until I want to
actually try and import data from my locations.

The current fix for 5.7 and 6.0.0beta is to use interp=TRUE. The cause
of
the problem seems to be the use of the 3D WINDOW, which the older code
in
the R-GRASS interface doesn't yet honour. I'm not at all sure what will
happen if your x,y locations are sites; the interface knows about
old-style sites, not vector sites. You may be obliged to use
system("") to
issue GRASS 5.7 commands to write out an ASCII file to read into R with
read.table().

Roger

Any help is appreciated.

Steve

---
Steven T. Stoddard

Program in Ecology, Evolution and Conservation Biology
University of Illinois at Urbana-Champaign

(217) 333-2235
302 Shelford Vivarium
606 E. Healy Ave
Champaign, IL 61820
http://www.life.uiuc.edu/~sstoddar

--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School
of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand@nhh.no

--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand@nhh.no