v.out.points

[Melissa Records]

"In an E-mail message, dnickisc at chief.ecn.uoknor.edu said:"
> 
> I am attempting to create a surface over digitized elevation contours.  The problem is that s.surf.tps requires a sites file and I have a line file.  I believe
> that v.out.points makes the necessary conversions, but I have been unable
> to find v.out.points on the moon or any documentation on the topic.  Any help
> would be greatly appreciated.
> 
> Daphne Nickisch
> 
Daphne,

Perhaps you're referring to "v.to.sites"?  Also, there are a couple
other surface generating programs in GRASS.  First, you'd have to 
run "v.to.rast" on your vector contour line file.  Then you can 
run "r.surf.contour" if you have continous contour lines (that is, 
there aren't any breaks in the contour lines where you'd put text
labels).  If your lines aren't continuous, you could try "r.surf.idw"
and "r.surf.idw2".  The GRASS 4.0 manual has pages for all of these
programs.

Here's a list that I got from Michael Shapiro and a brief blurb 
as to how they go about generating surfaces:


Inverse distance weighted interpolation:
	r.surf.idw        grid posted points
	r.surf.idw2       grid posted points (different search method)
	s.surf.idw        non-grid posted points
Contour interpolation from rasterized contours
	r.surf.contour
Thin plate splines with tension (helena's work)
	s.surf.tps


The word here at CERL is that the "s.surf.tps" beats all.