[GRASS-dev] support for raster time series in rgrass7?

[Sören Gebbert]

Hi Veronica,
can you please provide the tar.bzip2 file generated by R?

Best regards
Soeren

2015-08-18 13:20 GMT+02:00 Veronica Andreo <veroandreo at gmail.com>:
> Hello list,
>
> I'm just trying to use GRASS along with R for raster time series processing.
> I'm using GRASS temporal modules (t.rast.export/t.rast.import) along with
> the functions available in spacetime package (read.tgrass and write.tgrass)
> to complete workflow... However, after finally being able of getting
> write.tgrass to work, t.rast.import does not do the job... So, I don't know
> where exactly the problem is...
>
> The workflow I'm following is more or less like this:
>
> # GRASS (where I have my raster time series)
> t.rast.export input=temperature output=test_export_temp.tar.bzip2
> # extract data to check it's fine
> tar xvf test_export_temp.tar.bzip2
> # check text files
> cat list.txt ; cat proj.txt ; cat init.txt ; cat metadata.txt
>
> (if i import it back into GRASS with t.rast.import
> in=test_export_temp.tar.bzip2 out=test_import_temp base=t_test
> directory=/tmp it works smoothly)
>
> but, let's say I want to import it into R, do something there and get it
> back into GRASS. So,
>
> # In R
> library(spacetime)
> tgrass_test <- read.tgrass("test_export_temp.tar.bzip2")
>
> dim(tgrass_test)
> #[1] 135 150  12
>
> class(tgrass_test)
> #[1] "RasterStack"
> #attr(,"package")
> #[1] "raster"
>
> when, trying to follow the example in the "spacetime package" manual,
>
>> write.tgrass(tgrass_test, "myfile.tar.bzip2")
> Error in .local(x, filename, ...) :
>   filenames of source and target should be different
>
> # I changed map names (dunno if it makes sense) because of the previous
> error message
> for (i in c(1:12)) name_tgrass[i]<-paste("layer_",i,sep="")
> names(tgrass_test)<-name_tgrass
>
>> write.tgrass(tgrass_test, "myfile.tar.bzip2")
> tar: .: file changed as we read it
>
>> getwd()
> [1] "/tmp/RtmplJyK2L"
>
> # the file is created anyway... but when i try to import the created
> .tar.bzip2 into GRASS again, I get:
>
> GRASS 7.1.svn (nc_spm_08_grass7):~ > t.rast.import
> input=/tmp/RtmplJyK2L/myfile.tar.bzip2 out=tgrass_import basename=t_test_2
> directory=/tmp/RtmplJyK2L
> Traceback (most recent call last):
>   File
> "/home/veroandreo/software/grass-7.1.svn/dist.x86_64-unknown-linux-gnu/scripts/t.rast.import",
> line 123, in <module>
>     main()
>   File
> "/home/veroandreo/software/grass-7.1.svn/dist.x86_64-unknown-linux-gnu/scripts/t.rast.import",
> line 119, in main
>     set_current_region)
>   File
> "/home/veroandreo/software/grass-7.1.svn/dist.x86_64-unknown-linux-gnu/etc/python/grass/temporal/stds_import.py",
> line 216, in import_stds
>     gscript.fatal(_("Unable to find init file <%s>") % init_file_name)
>   File
> "/home/veroandreo/software/grass-7.1.svn/dist.x86_64-unknown-linux-gnu/etc/python/grass/script/core.py",
> line 643, in fatal
>     raise ScriptError(msg)
> grass.exceptions.ScriptError: Unable to find init file <init.txt>
>
> When I check the .tar.bzip2 file, the init.txt file is in fact there, but
> also the original maps... Can anybody explain how it is supposed to work??
> Or what I'm doing wrong? I attach the .tar.bzip2 file I get with
> t.rast.export
>
> I was wondering if there was any chance to include support for
> reading/writing spatio-temporal data sets in rgrass7, and make this kind of
> workflows a bit smoother, besides saving time and disk space... A somehow
> equivalent structure for GRASS raster data sets, but in R might be STFDF
> from spacetime package, "A class for spatio-temporal data with full
> space-time grid; for n spatial locations and m times, n x m observations are
> available", maybe it can be recycled??
>
> I'm using GRASS GIS 7.1 r65947 and R 3.2.1 under Fedora 21.
>
> Thanks a lot!!!
>
> Cheers,
> Vero
>
> ps: sorry for double posting :)
>
>
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