[GRASS-user] load vector map from PostGIS

Tue Feb 13 13:19:13 PST 2018

On Tue, Feb 13, 2018 at 2:58 PM, Moritz Lennert <
mlennert at club.worldonline.be> wrote:
>
> Le Tue, 13 Feb 2018 14:09:31 +0100 (CET),
> "Vilem Ded" <Ded.V at seznam.cz> a écrit :
>
> > Hi,
> > is there any possibility to download data  into local grass database
> > (topologcal) from remote postgis server? (without getting error)
> > Or is the issue still pending?
> > (http://osgeo-org.1560.x6.nabble.com/Unable-
> > to-link-to-postgis-postgresql-td5285313.html) I am using Python to
> > work with GRASS. And honestly, I got lost in outputs of db.*
> > functions:
>
> AFAIK, you should not need to go through all the db.* functions to
> import your data. Not much time to look any further into this, but check
> this thread:
> https://lists.osgeo.org/pipermail/grass-dev/2017-May/085032.html/
>
> In brief, you should be able to import your data with a simple v.in.ogr
> call, without any db.connect/db.login magic.

Some more explanations:
db.connect + db.login determine where attribute tables of GRASS vectors are
stored. These settings have nothing to do with OGR import. If you want to
change the default database where GRASS vector attribute tables are stored,
make sure you have write access to this database.

Regarding vector import, if in doubt, check with ogrinfo if the datasource
and layer can be accessed by OGR. If yes, v.in.ogr should succeed.

Markus M

>
> Moritz
>
> >
> > #set database and login
> > gscript.run_command('db.connect',
> > database="host=172.21.3.20,dbname=mydb", driver="pg",  verbose = True)
> > gscript.run_command('db.login', user="dbusername", password="passwd",
> > overwrite = True)
> >
> > #verifying connection
> > gscript.run_command('db.connect', flags='p')
> > output:
> > driver: pg
> > database: host=172.21.3.20,dbname=mydb
> > schema:
> > group:
> > #so everything looks fine so far
> >
> > #here comes the trouble - simple list tables in db
> > gscript.run_command('db.tables', flags='p', verbose = True)
> > output:
> > DBMI-PostgreSQL driver error:
> > Connection failed.
> > could not connect to server: No such file or directory
> >     Is the server running locally and accepting
> >     connections on Unix domain socket
> > "/var/run/postgresql/.s.PGSQL.5432"?
> >
> > DBMI-PostgreSQL driver error:
> > Connection failed.
> > could not connect to server: No such file or directory
> >     Is the server running locally and accepting
> >     connections on Unix domain socket
> > "/var/run/postgresql/.s.PGSQL.5432"?
> >
> > ERROR: Unable to open database <host=172.21.3.20,dbname=mydb>
> >
> > #but for example:
> > gscript.run_command('v.external',
> >                     input="PG:dbname=mydb host=172.21.3.20",
> >                     flags='l', overwrite =  True)
> > output:
> > --actuall list of all tables in mydb - so i CAN connect to the server!
> >
> > #same for mapping external link - following will create external link
> > gscript.run_command('v.external',
> >                     input="PG:dbname=mydb host=172.21.3.20
> > user=dbusername password=password",
> >                     layer="myschema.mytable", output='outpoints,
> > overwrite = True)
> > output:
> > WARNING: No key column detected.
> > WARNING: Feature table <outpoints> has no primary key defined. Unable
> > to define DB links.
> > WARNING: Feature table <outpoints> has no primary key defined
> > WARNING: Random read is not supported for this layer. Unable to build
> >          topology.
> > v.external complete. Link to vector map <outpoints> created.
> >
> > #weird, because i have primary key defined in the table, following is
> > printing description of that external link
> > gscript.vector_info("outpoints")
> >
> > #if i try to load data from database
> > gscript.run_command('v.in.ogr',
> >                     input="PG:dbname=mydb host=172.21.3.20",
> >                     layer='myschema.mytable',geometry="mygeomcolumn",
> > output = "outpoints2", overwrite =  True, type="point")
> > output:
> > Check if OGR layer <myschema.mytable> contains polygons...
> >  100%�����
> > WARNING: Vector map <outpoints2> already exists and will be
> > overwritten DBMI-PostgreSQL driver error:
> > Connection failed.
> > could not connect to server: No such file or directory
> >     Is the server running locally and accepting
> >     connections on Unix domain socket
> > "/var/run/postgresql/.s.PGSQL.5432"?
> >
> > DBMI-PostgreSQL driver error:
> > Connection failed.
> > could not connect to server: No such file or directory
> >     Is the server running locally and accepting
> >     connections on Unix domain socket
> > "/var/run/postgresql/.s.PGSQL.5432"?
> >
> > WARNING: Unable to open database <host=172.21.3.20,dbname=macfishdb>
> > by driver <pg>
> > WARNING: Unable open database <host=172.21.3.20,dbname=macfishdb> by
> > driver <pg>
> > WARNING: Unable to find table <outpoints2> linked to vector map
> > <lp_grass> Creating attribute table for layer
> > <at_macfish.loggerpos>... DBMI-PostgreSQL driver error:
> > Connection failed.
> > could not connect to server: No such file or directory
> >     Is the server running locally and accepting
> >     connections on Unix domain socket
> > "/var/run/postgresql/.s.PGSQL.5432"?
> >
> > DBMI-PostgreSQL driver error:
> > Connection failed.
> > could not connect to server: No such file or directory
> >     Is the server running locally and accepting
> >     connections on Unix domain socket
> > "/var/run/postgresql/.s.PGSQL.5432"?
> >
> > WARNING: Unable to open database <host=172.21.3.20,dbname=mydb> by
> >          driver <pg>
> > ERROR: Unable to open database <host=172.21.3.20,dbname=mydb> by
> >        driver <pg>
> >
> > My version of grass:
> > GRASS version:
> > 7.4.0
> > GRASS SVN revision:
> > exported
> > Build date:
> > 2018-01-26
> > Build platform:
> > x86_64-pc-linux-gnu
> > GDAL:
> > 2.2.2
> > PROJ.4:
> > 4.9.2
> > GEOS:
> > 3.5.1
> > SQLite:
> > 3.11.0
> > Python:
> > 2.7.12
> > wxPython:
> > 3.0.2.0
> > Platform: Linux-4.4.0-112-generic-x86_64-with-Ubuntu-16.04-xenial
> >
> > Version of python:
> >
> > Python 2.7.12 64bits
> >
> > Content of my .grass7/dblogin:
> > pg|host=172.21.3.20, dbname=mydb|dbusername|passwd||
> >
sqlite|$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db|dbusername|passwd||
> > pg|macfishdb|dbusername|passwd||
> > pg|host=172.21.3.20,dbname=mydb|dbusername|passwd||
> >
> > Thank you for any comment
> > Dead Vil
> >
> >
>
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