[GRASS-user] importing missing values via v.in.ascii for subsequent interpolation

[Luigi Ponti]

Hello,

I am trying to import ASCII files with v.in.ascii for subsequent 
interpolation via v.surf.idw. The problem is that if I put NULL for 
missing values, v.in.ascii complains about the column being of type 
DOUBLE and fails. On the other hand if I put missing values as just '', 
as suggested at
http://www.intevation.de/rt/webrt?serial_num=2763&display=History
then v.surf.rst seems to use those missing values as ZERO values in 
computing the weighted average.

I tried with something like

	v.db.update map=myMap column=myColumn value="NULL" \
		where=myColumn=''

But it did not work.

Does anybody have a way around this?

Regards,

Luigi