[GRASS-user] passing output from GRASS to R.

Milton_Cezar_Ribeiro · May 4, 2009, 6:57pm

Dear all,

I am running R inside GRASS 6.4 and I can see a list
of all my raster files when I type (from the R session)

system(“g.list rast”)

But I would like to pass the list of rasters to a vector object in R.

I tryed innocently this, but not worked:

my.rast.list<-system(“g.list rast”)

I also would like to define a pattern of raster names to the g.list command,
like only return that raster names that have “output” on the name.

By the way, I am running GRASS inside MSYS, under windows.

Cheers

milton

neteler · May 4, 2009, 9:33pm

On Mon, May 4, 2009 at 8:57 PM, Milton Cezar Ribeiro
<miltinho.astronauta@gmail.com> wrote:

Dear all,

I am running R inside GRASS 6.4 and I can see a list
of all my raster files when I type (from the R session)

system("g.list rast")

But I would like to pass the list of rasters to a vector object in R.

I tryed innocently this, but not worked:

my.rast.list<-system("g.list rast")

Try this:

rasterfiles <- read.table(textConnection(system("g.mlist rast",intern = TRUE)))
str(rasterfiles)

'data.frame': 42 obs. of 1 variable:
$ V1: Factor w/ 42 levels "aspect","basin_50K",..: 31 1 2 3 4 5 6 7 8 9 ...

rasterfiles

V1
1 myfacility
2 aspect
3 basin_50K
4 boundary_county_500m
...

I also would like to define a pattern of raster names to the g.list command,
like only return that raster names that have "_output_" on the name.

So:

rasterfiles <- read.table(textConnection(system("g.mlist rast pattern="*_output_*",intern = TRUE)))
str(rasterfiles)

By the way, I am running GRASS inside MSYS, under windows.

Please report if above works (as it does on Linux).

Markus

Milton_Cezar_Ribeiro · May 5, 2009, 12:28am

Hi Markus,

Under windows I needed only small changes

rasterfiles ← read.table(textConnection(system(“g.mlist.exe rast pattern=output”, intern = TRUE)))

Thanks a lot,

milton

2009/5/4 Markus Neteler <neteler@osgeo.org>

On Mon, May 4, 2009 at 8:57 PM, Milton Cezar Ribeiro
<miltinho.astronauta@gmail.com> wrote:

Dear all,

I am running R inside GRASS 6.4 and I can see a list
of all my raster files when I type (from the R session)

system(“g.list rast”)

But I would like to pass the list of rasters to a vector object in R.

I tryed innocently this, but not worked:

my.rast.list<-system(“g.list rast”)

Try this:

rasterfiles ← read.table(textConnection(system(“g.mlist rast”,intern = TRUE)))
str(rasterfiles)
‘data.frame’: 42 obs. of 1 variable:
$ V1: Factor w/ 42 levels “aspect”,“basin_50K”,…: 31 1 2 3 4 5 6 7 8 9 …
rasterfiles
V1
1 myfacility
2 aspect
3 basin_50K
4 boundary_county_500m
…

I also would like to define a pattern of raster names to the g.list command,
like only return that raster names that have “output” on the name.

So:

rasterfiles ← read.table(textConnection(system("g.mlist rast pattern=“output”,intern = TRUE)))
str(rasterfiles)

By the way, I am running GRASS inside MSYS, under windows.

Please report if above works (as it does on Linux).

Markus

Roger_Bivand · May 5, 2009, 8:06am

From spgrass6 0.6-*, and after installing the R XML package (off CRAN but

installs automatically from Prof. Ripley's extra Windows repository if you
are on Windows), you can use:

rasterfiles <- execGRASS("g.mlist", parameters=list(type="rast",
pattern="*ele*"), intern=TRUE)

(here from spearfish, which has *ele* rasters in PERMANENT). Do:

parseGRASS("g.mlist")

to see the flags and parameters. As Markus pointed out, intern=TRUE is the
key argument, to get the output of the GRASS command back into the R
workspace. There are issues with regard to quoting between platforms for a
few GRASS commands, but most things now work. I tried this on MSYS Windows
native 6.4.0 RC4.

Roger

Milton Cezar Ribeiro wrote:

Hi Markus,

Under windows I needed only small changes

rasterfiles <- read.table(textConnection(system("g.mlist.exe rast
pattern=*output*", intern = TRUE)))
Thanks a lot,

milton

2009/5/4 Markus Neteler <neteler@osgeo.org>

On Mon, May 4, 2009 at 8:57 PM, Milton Cezar Ribeiro
<miltinho.astronauta@gmail.com> wrote:
> Dear all,
>
> I am running R inside GRASS 6.4 and I can see a list
> of all my raster files when I type (from the R session)
>
> system("g.list rast")
>
> But I would like to pass the list of rasters to a vector object in R.
>
> I tryed innocently this, but not worked:
>
> my.rast.list<-system("g.list rast")

Try this:

> rasterfiles <- read.table(textConnection(system("g.mlist rast",intern =
TRUE)))
> str(rasterfiles)
'data.frame': 42 obs. of 1 variable:
$ V1: Factor w/ 42 levels "aspect","basin_50K",..: 31 1 2 3 4 5 6 7 8 9
...
> rasterfiles
V1
1 myfacility
2 aspect
3 basin_50K
4 boundary_county_500m
...

> I also would like to define a pattern of raster names to the g.list
command,
> like only return that raster names that have "_output_" on the name.

So:
> rasterfiles <- read.table(textConnection(system("g.mlist rast
pattern="*_output_*",intern = TRUE)))
> str(rasterfiles)

> By the way, I am running GRASS inside MSYS, under windows.

Please report if above works (as it does on Linux).

Markus

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-----
Roger Bivand
Economic Geography Section
Department of Economics
Norwegian School of Economics and Business Administration
Helleveien 30
N-5045 Bergen, Norway

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Milton_Cezar_Ribeiro · May 5, 2009, 12:31pm

Thanks for both, Markus and Roger Bivand.

Cheers

milton

2009/5/5 Roger Bivand <Roger.Bivand@nhh.no>

From spgrass6 0.6-*, and after installing the R XML package (off CRAN but
installs automatically from Prof. Ripley’s extra Windows repository if you
are on Windows), you can use:

rasterfiles ← execGRASS(“g.mlist”, parameters=list(type=“rast”,
pattern=“ele”), intern=TRUE)

(here from spearfish, which has ele rasters in PERMANENT). Do:

parseGRASS(“g.mlist”)

to see the flags and parameters. As Markus pointed out, intern=TRUE is the
key argument, to get the output of the GRASS command back into the R
workspace. There are issues with regard to quoting between platforms for a
few GRASS commands, but most things now work. I tried this on MSYS Windows
native 6.4.0 RC4.

Roger

Milton Cezar Ribeiro wrote:

Hi Markus,

Under windows I needed only small changes

rasterfiles ← read.table(textConnection(system(“g.mlist.exe rast
pattern=output”, intern = TRUE)))
Thanks a lot,

milton

2009/5/4 Markus Neteler <neteler@osgeo.org>

On Mon, May 4, 2009 at 8:57 PM, Milton Cezar Ribeiro
<miltinho.astronauta@gmail.com> wrote:

Dear all,

I am running R inside GRASS 6.4 and I can see a list
of all my raster files when I type (from the R session)

system(“g.list rast”)

But I would like to pass the list of rasters to a vector object in R.

I tryed innocently this, but not worked:

my.rast.list<-system(“g.list rast”)

Try this:

rasterfiles ← read.table(textConnection(system(“g.mlist rast”,intern =
TRUE)))
str(rasterfiles)
‘data.frame’: 42 obs. of 1 variable:
$ V1: Factor w/ 42 levels “aspect”,“basin_50K”,…: 31 1 2 3 4 5 6 7 8 9
…
rasterfiles
V1
1 myfacility
2 aspect
3 basin_50K
4 boundary_county_500m
…

I also would like to define a pattern of raster names to the g.list
command,
like only return that raster names that have “output” on the name.

So:

rasterfiles ← read.table(textConnection(system("g.mlist rast
pattern=“output”,intern = TRUE)))
str(rasterfiles)

By the way, I am running GRASS inside MSYS, under windows.

Please report if above works (as it does on Linux).

Markus

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

Roger Bivand
Economic Geography Section
Department of Economics
Norwegian School of Economics and Business Administration
Helleveien 30
N-5045 Bergen, Norway

–
View this message in context: http://n2.nabble.com/passing-output-from-GRASS-to-R.-tp2788835p2791576.html
Sent from the Grass - Users mailing list archive at Nabble.com.

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