Hello list,
I downloaded generalized coastlines from: http://openstreetmapdata.com/data/generalized-coastlines and as they are in mercator projection (epsg:3857) and I’m working in eu_laea, i wanted to use v.import to reproject (and subset to my region) on the fly… but I can’t get v.import nor v.proj to work…
This is the command I’m using (copied from the GUI) and the error:
v.import input=coastlines_z8.shp epsg=3857 datum_trans=0 → the same with whatever value > 0 that I put here
WARNING: All available OGR layers will be imported into vector map <coastlines_z8>
Projection information updated
WARNING: All available OGR layers will be imported into vector map <coastlines_z8>
Importing </home/veroandreo/gisdata/coastlines-generalized-3857/coastlines_z8.shp> …
WARNING: All available OGR layers will be imported into vector map <coastlines_z8>
Check if OGR layer <coastlines_z8> contains polygons…
Default driver / database set to:
driver: sqlite
database: $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db
Importing 30179 features (OGR layer <coastlines_z8>)…
Building topology for vector map coastlines_z8@PERMANENT…
Registering primitives…
30179 primitives registered
2796082 vertices registered
Building areas…
[…]
Reprojecting <coastlines_z8>…
Reprojecting primitives …
WARNING: pj_transform() failed: failed to load datum shift file
ERROR: Unable to re-project vector map coastlines_z8@PERMANENT from <temp_import_location_12909>
ERROR: Unable to to reproject vector <coastlines_z8>
Moreover, if I use datum_trans=-1 which is supposed to throw the list of parameters, I get the following error:
v.import input=coastlines_z8.shp epsg=3857 datum_trans=-1
ERROR: No output format specified, define one of flags -p, -g, -j, or -w
Traceback (most recent call last):
File “/home/veroandreo/software/grass-7.3.svn/dist.x86_64
-pc-linux-gnu/scripts/v.import”, line 290, in
sys.exit(main())
File “/home/veroandreo/software/grass-7.3.svn/dist.x86_64
-pc-linux-gnu/scripts/v.import”, line 158, in main
datum_trans=options[‘datum_trans’])
File “/home/veroandreo/software/grass-7.3.svn/dist.x86_64
-pc-linux-gnu/etc/python/grass/script/core.py”, line 410, in
run_command
return handle_errors(returncode, returncode, args,
kwargs)
File “/home/veroandreo/software/grass-7.3.svn/dist.x86_64
-pc-linux-gnu/etc/python/grass/script/core.py”, line 329, in
handle_errors
returncode=returncode)
grass.exceptions.CalledModuleError: Module run None
[‘g.proj’, ‘epsg=3857’, ‘datum_trans=-1’] ended with error
Process ended with non-zero return code 1. See errors in the
(error) output.
Then, I created a new location from the .prj and imported the file. So, I went to my target location to reproject with the good old v.proj but I get the same warning message at the end and the file is not projected:
v.proj location=mercator mapset=PERMANENT input=coastlines_z8
WARNING: pj_transform() failed: failed to load datum shift file
ERROR: Unable to re-project vector map coastlines_z8@PERMANENT from
In conclusion:
-
can someone illustrate on what datum_trans means in v.import, what number goes there and/or provide a working example, please?
-
what is the datum shift file and where is it supposed to be?
Thanks a million in advance for any help/hint!
Best,
Vero
ps1: I’m using grass 73 svn r69040M under Fedora 24
ps2: my way-around to get the file imported was: opening the mercator file in qgis, saving as eu_laea and importing with v.in.ogr into my eu_laea location (suboptimal, but works)
(I wonder what is qgis using then to make the global data re-projection…)