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

Markus Neteler neteler at osgeo.org
Thu May 16 13:04:10 PDT 2013

On Thu, May 16, 2013 at 9:15 AM, 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.

How about having a "exclude" parameter in v.in.ascii POINT mode?

Eg. g.mlist has
     Map name exclusion pattern (default: none)
  See: http://grass.osgeo.org/grass70/manuals/g.mlist.html


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