[GRASS-user] SQL query in python scripts using v.to.rast

[Alessandro Sebastiani]

thank you Mika, it's working!

Il giorno dom 11 nov 2018 alle ore 13:40 Micha Silver <tsvibar at gmail.com>
ha scritto:

> Here's a correction to the format of the "where" clause that should work:
>
>
> *i*mport grass.script as gscript
> types = ("primary" , "secondary" , "tertiary" , "service" , "pedestrian" ,
> "footway" , "residential" , "path")
> for typ in types:
>
>     where_str = ("type = '%s'" % typ)   # Added single quotes around the
> %s
>
>     outrast = "_".join(["type", typ])
>     gscript.run_command ("v.to.rast",
>             input = "road_clip",
>             type = "line",
>             where = where_str,
>             output = outrast,
>             use = "attr" , attribute_column = "cat")
>
>
>
> On 11/11/18 12:02 PM, Alessandro Sebastiani wrote:
>
> Hello to everybody ,
> i* tried with this piece of code, following suggestios by both:*
> # note that for the moment i reduced the street types to 3
> >>>types = ("primary" , "secondary" , "tertiary")
> >>>for typ in types:
> >>>>    gscript.run_command ("v.to.rast" , input = "road_clip" , type =
> "line" , where = "type=%s" % typ , output = ("r"+typ) , use = "attr" ,
> attribute_column = "cat")
>
> *nevertheless, i still get the following error message*
> DBMI-SQLite driver error:
> Error in sqlite3_prepare():
> SELECT cat FROM road_clip WHERE type=primary
> near "primary": syntax error
> DBMI-SQLite errore del driver:
> Error in sqlite3_prepare():
> SELECT cat FROM road_clip WHERE type=primary
> near "primary": syntax error
> ERROR: Impossible to select recod from table <road_clip>
> Traceback (most recent call last):
>   File "/home/alessandro/Scrivania/script_grass/rast_quer_st
> ats_exp.py", line 6, in <module>
>     gscript.run_command ("v.to.rast" , input = "road_clip" ,
> type = "line" , where = "type=%s" % typ , output = ("r"+typ)
> , use = "attr" , attribute_column = "cat")
>   File "/usr/lib/grass74/etc/python/grass/script/core.py",
> line 421, in run_command
>     return handle_errors(returncode, returncode, args,
> kwargs)
>   File "/usr/lib/grass74/etc/python/grass/script/core.py",
> line 332, in handle_errors
>     returncode=returncode)
> grass.exceptions.CalledModuleError: L'esecuzione del modulo
> None ['v.to.rast', 'use=attr', 'attribute_column=cat',
> 'type=line', 'input=road_clip', 'output=rprimary',
> 'where=type=primary'] è terminata con errori
> Processo terminato con codice di return diverso da zero 1.
>
>
> (Sun Nov 11 10:53:56 2018) Comando terminato (0 sec)
>
> I read both error message and my piece of code time again and again, i was
> not able to detect what i am doing wong!
>
>
> Il giorno ven 9 nov 2018 alle ore 13:15 Micha Silver <tsvibar at gmail.com>
> ha scritto:
>
>> I would do as follows:
>>
>> (Notice that each street type will become a *separate* raster)
>>
>>
>> On 11/9/18 1:49 PM, Alessandro Sebastiani wrote:
>>
>> Dear all
>> i have a vector (downloaded from OpenStreetmap) with all the streets in
>> my study area. Streets are divided in categories (there is a specific
>> string column in the db). now i want to convert to raster each category
>> separately. I now how to do that separately, but i was not able to automate
>> that in a python script. here it is what i wrote:
>> *>>>*import grass.script as gscript
>> *>>>*types = ("primary" , "secondary" , "tertiary" , "service" ,
>> "pedestrian" , "footway" , "residential" , "path")
>> *>>>*for typ in types:
>>
>>     where_str = ("type = %s" % typ)
>>
>>     outrast = "_".join(["type", typ])
>>
>>     gscript.run_command("v.to.rast",
>>
>>             input = "road_clip", type = "line", where = where_str,
>>
>>             output = outrast, use="attr", attribute_column = "cat" )
>>
>> *>>>> *   gscript.run_command ("v.to.rast" , input = "road_clip" , type
>> = "line" , where ="type"=typ , output = types, use = "attr" ,
>> attribute_column = "cat").
>> *I got the following traceback:*   File
>> "/home/alessandro/GRASSDATA/5_citta_def/5_citt_def/.tmp
>> /alessandro-Lenovo-G50-70/5500.6.py", line 6
>>     gscript.run_command ("v.to.rast" , input = "road_clip" ,
>> type = "line" , where ="type"=typ , output = types, use =
>> "attr" , attribute_column = "cat")
>>                               ^
>> SyntaxError: invalid syntax
>>
>> i guess the syntax error is in the way i set the query, but i'm not sure.
>> Thanks to everybody,
>>
>> _______________________________________________
>> grass-user mailing listgrass-user at lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/grass-user
>>
>> --
>> Micha Silver
>> Ben Gurion Univ.
>> Sde Boker, Remote Sensing Lab
>> cell: +972-523-665918
>>
>>
> _______________________________________________
> grass-user mailing listgrass-user at lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/grass-user
>
> --
> Micha Silver
> Ben Gurion Univ.
> Sde Boker, Remote Sensing Lab
> cell: +972-523-665918
>
>
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