Q: s.surf.idw

[A. Rosenberger]

We do have a site-list of field measurements
(soil resistivity) which we interpolate to
raster by means of s.surf.idw.

Z-values in the site-list are floating-point
ranging from 0.0 to 25.0.

The output of s.surf.idw creates a raster map with
only five categories. 

I need at least 255 categories, how can this be
accomplished ?

Do I have to build categories outside grass, i.e.
create the site-list with categories for Z-values 
instead of using original (measured) data ??

Thanks for your help,

Andreas
Dept. of Geophysics
Univ. of Bremen