[STATSGRASS] How does Gstat handle NULL values in GRASS

[Markus Neteler]

On Thu, Jul 04, 2002 at 01:01:06PM +0200, Edzer J. Pebesma wrote:
> Ulrich,
> 
> Gstat calls the grass function G_is_null_value() (which is in libgis.a)
> to determine whether a cell value is considered "missing value" (null
> in Grass) or not, so I guess you'd have to do something with your -9999
> values within grass, or while importing things to grass, to make sure 
> they're dealt with as missing/null values.
> Edzer

Ulrich,

here r.null is your friend to convert -9999 to a real NULL
value.

Best regards,

 Markus

> Ulrich Leopold wrote:
> > 
> > not really. but i applied gstat outside of grass with grass ascii maps. this
> > worked quite fine. so i guess it will work within grass the same way as
> > gstat recognized -9999 as missing values(NULL values). But i still have to
> > explore this for being sure about it.
> >