initGRASS issue with version 0.2.8

[VincentGodard]

Hello,

I am using rgrass7 to setup throwaway GRASS locations.

GRASS version : 7.8.6 (UbuntuGIS stable PPA) R version : 3.6.3 Ubuntu 20.04.4

With rgrass7 0.2.6 I am routinely using :

gisbase = "/usr/lib/grass78/"
rgrass7::initGRASS(gisbase,home=tempdir(),mapset="PERMANENT",override = TRUE)

and then calls to g.proj and g.region to set the location properties (through execGRASS).

I know I could use the SG option to set everything at once, but in the past I had a few issues with some rasters when moving back and forth between GRASS and R (slight changes in the resolution) so I prefer to define the location properties this way.

Now with rgrass7 0.2.8 :

rgrass7::initGRASS(gisbase,home=tempdir(),mapset="PERMANENT",override = TRUE)

returns the following error :

Error in execGRASS("g.proj", flags = c("w"), intern = TRUE, ignore.stderr = ignore.stderr) : 
  The command:
g.proj -w
produced an error (1) during execution:
ATTENTION: fichier <PROJ_INFO> introuvable pour le secteur
           <file3f47d24ad6933>
ATTENTION: fichier <PROJ_UNITS> introuvable pour le secteur
           <file3f47d24ad6933>
ERREUR : Fichiers de projection manquant

Due to the non-existing projection information at this stage in the location (which was not an issue with 0.2.6).

I tried to use the SG option but I also get an error in this case (rgrass7 0.2.8), where it seems to expect a latlon system whereas the input terra SpatRaster (dem) is UTM31N.

dem0 <- as(raster(dem), "SpatialGrid")
rgrass7::initGRASS(gisbase,SG=dem0,home=tempdir(),mapset="PERMANENT",override = TRUE)
Error in execGRASS("g.region", save = "input", flags = "overwrite") : 
  The command:
g.region --overwrite save=input
produced an error (1) during execution:
ERREUR : Lattitude Nord illégale : 4.91676e+06

Where 4.91676e+06 is the ymax (northing) of dem, and obviously not a latitude.

> dem
class       : SpatRaster 
dimensions  : 1596, 1654, 1  (nrow, ncol, nlyr)
resolution  : 30, 30  (x, y)
extent      : 539757.5, 589377.5, 4868879, 4916759  (xmin, xmax, ymin, ymax)
coord. ref. : WGS 84 / UTM zone 31N (EPSG:32631) 
source      : memory 
name        : srtm_cevennes_utm 
min value   :                85 
max value   :              1672 

Would you have any idea about what could cause this change of behavior ?

Best regards, Vincent

[rsbivand]

Please clarify what terra dem is? Is it the internal representation of terra/inst/ex/elev.tif?

For the first part of your issue, please test:

remotes::install_github("rsbivand/rgrass", ref="init_no_SG_53")

in your setting. Note that although I've tested this with GRASS 7.8.6, it is expected that issues are not retrospective; your R and GRASS versions are well behind current. This fix also works for GRASS 8.0.1 which had the same error with rgrass7 0.2-8; I use R 4.1.3.

[VincentGodard]

Hi Roger,

(1) dem is SpatRaster (SRTM DEM I use for testing), no it is not terra/inst/ex/elev.tif.

> dem
class       : SpatRaster 
dimensions  : 1596, 1654, 1  (nrow, ncol, nlyr)
resolution  : 30, 30  (x, y)
extent      : 539757.5, 589377.5, 4868879, 4916759  (xmin, xmax, ymin, ymax)
coord. ref. : WGS 84 / UTM zone 31N (EPSG:32631) 
source      : memory 
name        : srtm_cevennes_utm 
min value   :                85 
max value   :              1672 

(2) I've tested with the version you sent, and it seems to be working now.

Thanks a lot, Vincent

[rsbivand]

Thanks!

What happens using dem as SG= as a SpatRaster object, in addition to trying as a SpatialGridDataFrame? If this still fails, please make the object available for further debugging.

[VincentGodard]

Passing dem as a SpatRaster works. Passing dem as either a SpatialGrid or SpatialGridDataFrame leads to the following error (Error : illegal North latitude):

Error in execGRASS("g.region", save = "input", flags = "overwrite", ignore.stderr = ignore.stderr) : 
  The command:
g.region --overwrite save=input
produced an error (1) during execution:
ERREUR : Lattitude Nord illégale : 4.91676e+06

I put dem as a tiff here if needed :

https://filesender.renater.fr/?s=download&token=d360f37f-de36-44c3-858d-923347a96ee6

[rsbivand]

Thanks, very useful, a simple logic error in 0.2-8. I'll merge this branch into main shortly.

[rsbivand]

rgrass7 1.2-9 on CRAN!

[VincentGodard]

I can confirm everything works on my side. Thanks Roger, Vincent