[GRASSLIST:4019] adding a field from raster image to existing site data

[Thomas Dewez]

Dear all,

My project is moving on thanks to your help. The next question I'd have is
to interpolate a DEM for which I have these information:
1. irregularly spaced Z stored in an raster map (2.5 million data points!)
2. corresponding precision for Z posts in a second raster image.

Are site coverages the only sources that I can feed to s.surf.rst or can I
interpolate a spline with tension directly from a raster map? By the way,
are sites map plain ASCII files?

If site coverage is the only solution, then how can I combine both raster
map inside a single site map? I want to use the precision image as the
"smoothing attribute" of the interpolation. So how do I make the precision
raster map become attribute 2 of the sites?

Finally, s.surf.rst is extremely CPU intensive. What are the "cooking
tricks" to use to speed up/avoid slowing down the process?

Thanks for your help,

Thomas