[GRASS-dev] null value in vector (v.in.ascii, v.surf.*)

Yann Chemin yann.chemin at gmail.com
Thu May 16 00:40:53 PDT 2013

Thanks Hamish,

thinking in vector mode is different than in raster mode...


On 16 May 2013 12:45, Hamish <hamish_b at yahoo.com> wrote:
> Yann:
>> Does this mean that v.in.ascii recognizes 99999.99 as a grass
>> vector null value?
>> If I use 99999.99 in v.surf.* will it be discarded from the
>> interpolation?
> Nope, the 'grep -v' means that entire row of data is excluded
> from the datastream and never sent to v.in.ascii in the first
> place.
> I just used NULL=99999.99 as an example, NULL= could be set to
> anything.
> If you need the x,y row there, but with empty values instead of
> 9999s in some column, then db.execute might be a faster way
> than v.db.update to clear them (only open and close the DB once),
> but v.extract with where="value < 9998" might be fastest of all.
> Hamish

Yann Chemin
Researcher at IWMI
Skype/FB: yann.chemin

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