[GRASS-user] v.extract where clause with puthon script

[Markus Neteler]

On Sat, Feb 14, 2015 at 4:00 PM, Roy <royroge at outlook.com> wrote:
> Dear all,
>
> i'm trying to extract some vectors using attribute names using python
> script: (grass 6.4.4)
>
> i have a column with "des" values : river, canal
> and i have to extract only the features of type 'canal'
> then of type 'river' and so on...
>
> #######################################
>
> import grass.script as grass
>
> env = grass.gisenv()
>
> grass.run_command('v.extract', input='idro', output='canal_idro', where='des
> = canal', overwrite='True')
>
> #################################################################################
>
> maybe i'm missing the correct sintiax of the "where" clause  because i only
> get a buffer overflow as result,

You need to quote the text string "canal", i.e. where='des = "canal"'

Here a NC dataset example

grass.run_command('v.extract', input='roadsmajor', output='nc55',
where='ROAD_NAME = "NC-55"', overwrite='True')

HTH,
Markus