[GRASS-dev] [GRASS GIS] #2660: r.external.out: support paths relative to the mapset, and variables

[GRASS GIS]

#2660: r.external.out: support paths relative to the mapset, and variables
----------------------------+-----------------------------------------------
 Reporter:  sbl             |       Owner:  grass-dev@…              
     Type:  defect          |      Status:  new                      
 Priority:  normal          |   Milestone:  7.0.1                    
Component:  Raster          |     Version:  svn-releasebranch70      
 Keywords:  r.external.out  |    Platform:  Unspecified              
      Cpu:  Unspecified     |  
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 Currently, r.external.out uses absolute paths which may be incorrect if
 the database is accessed via a networked filesystem (or even a local
 filesystem if the mount point changes).

 If the directory given to r.external.out is relative (doesn't begin with a
 "/"), it's converted to an absolute path relative to the current mapset
 directory.

 Thereafter, any created maps will have the absolute path in their GDAL
 link (i.e. the cell_misc/<map>/gdal file).

 Thus, maps created with r.external.out can't be read if the database
 directory has "moved" relative to its location when the map was created.

 It would be helpful if paths relative to the mapset could be supported,
 and maybe additional options, e.g. the ability to use environment
 variables in paths

 Here is a test case in order to reproduce the issue:

 First I created a new and empty GRASS Location "test" on a network storage
 (NFS) from the Linux Server. This GRASS DB is mounted on LINUX (through
 mount.cifs) to `/home/stefan/R_raw_data/test'. On Windows the "Network
 drive" is mapped to " R:\Raw_data\test "

 Within this Location I crated a mapset "linux" (from the Linux Server) and
 a mapset "windows"  from my Windows 7 workstation.

 1st test case: Linux to Windows:
 On the Linux  server, and in the "linux" mapset I did:


 {{{
 r.external.out --verbose directory="/home/stefan/R_raw_data/test"
 extension=".tif" format="GTiff"
 g.region -p n=1 s=0 e=1 w=0 res=0.1
 r.mapcalc expression="linux_map=1"
 }}}

 On my Win 7 box I did:

 d.rast map= linux_map @linux
 Here I got the following error message:

 {{{
 Command 'd.rast map=linux_map at linux' failed
 Details: ERROR 4: `/home/stefan/R_raw_data/test/linux_map.tif' does not
 exist in the file system, and is not recognised as a supported dataset
 name.
 }}}

 Then I tried relative paths:
 On Linux:

 {{{
 r.external.out --verbose directory="../../" extension=".tif"
 format="GTiff"
 r.mapcalc expression="linux_map=1" --o
 }}}

 Error message on Windows changes to:

 {{{
 Command 'd.rast map=linux_map at linux' failed
 Details: ERROR 4:
 `/home/stefan/R_raw_data/test/newLocation/linux/../..//linux_map.tif' does
 not exist in the file system, and is not recognised as a supported dataset
 name.
 }}}

 2nd test case: Windows to Linux:
 On my Windows box (and in the "windows" mapset) I did:

 {{{
 r.external.out --verbose directory="R:\Raw_data\test" extension=".tif"
 format="GTiff"
 r.mapcalc expression=windows_map=1
 }}}

 Which results in the following error message:

 {{{
 ERROR: Unable to make mapset element R:\Raw_data\test
 (R:\Raw_data\test/newLocation/windows/R:\Raw_data\test): No such file or
 directory
 }}}


 Then I tried relative paths:

 {{{
 r.external.out --verbose directory="../../" extension=.tif format=GTiff
 }}}


 The relative paths work for the Windows side. However, back on Linux I
 tried:
 d.rast map=windows_map at windows and got the following error message:


 {{{
 Command 'd.rast map=windows_map at windows' failed
 Details: ERROR 4:
 `R:\Raw_data\test/newLocation/windows/../..//windows_map.tif' does not
 exist in the file system, and is not recognised as a supported dataset
 name.
 }}}

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/2660>
GRASS GIS <http://grass.osgeo.org>