[R-sig-Geo] Issue with rgrass7 and readRAST

[Roger Bivand]

Tom

On Fri, 10 Jul 2020, Thomas Adams wrote:

> Hi,
>
> I'm using R in combination with GRASS GIS 7.8.3, attempting to read a GRASS
> raster file into R with the rgrass7 interface. I have done this kind of
> thing countless times previously without problems. It's quite possible I am
> running into memory issues, but my Ubuntu 18.04 Linux computer has 32 GB of
> RAM.
>

I have not succeeded in reproducing this, I'm afraid. I created a location 
with cell counts to match, and ran r.out.bin first to check whether there 
were any issues writing the data to a temporary file. Then I ran the 
equivalent of your command (readRAST()), again without problems. I'm on a 
16 GB PC, so the problem is puzzling. I'm curious about the free space on 
your

/media/teaiii/development/grass/greensboro_mercator/teaiii/.tmp/
teaiii-Leopard-WS

directory. Did you check whether any output arrived there, since the error 
message is coming from r.out.bin?

The error is on line 53 in raster/r.out.bin/main.c, when the system 
function fwrite() returns an error.

Thanks for your patience.

Roger


> My GRASS raster file:
>
> Type of Map:  raster               Number of Categories: 0
> Data Type:    CELL
> Rows:         22663
> Columns:      28794
> Total Cells:  652558422
> ~90m resolution
>
> Using...
>
> srtm <- readRAST("mozambique_srtm_patch",cat=FALSE)
>
> After quite some time, I get...
>
> Error in execGRASS("r.out.bin", flags = rOutBinFlags, input = vname[i],  :
>  The command:
> r.out.bin -b -i input=mozambique_srtm_patch
> output=/media/teaiii/development/grass/greensboro_mercator/teaiii/.tmp/teaiii-Leopard-WS/mozambique_srtm_patch
> bytes=4 null=-81
> produced an error (1) during execution:
> Creating BIL support files...
> Exporting raster as integer values (bytes=4)
> ERROR: Error writing data
> In addition: Warning messages:
> 1: In showSRID(uprojargs, format = "PROJ", multiline = "NO") :
>  Discarded ellps unknown in CRS definition: +proj=merc +lat_ts=0 +lon_0=0
> +x_0=0 +y_0=0 +R=6378137 +units=m +no_defs
> 2: In showSRID(uprojargs, format = "PROJ", multiline = "NO") :
>  Discarded datum unknown in CRS definition
>
> Libraries loaded include: sp, rgrass7, rgdal, raster...
>
> Any thoughts?
>
> Best,
> Tom
>
>

-- 
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: Roger.Bivand using nhh.no
https://orcid.org/0000-0003-2392-6140
https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en