[GRASSLIST:7907] Re: Hutchinson's Adaptive Alogrithm for sound DEMs?

[Dylan Beaudette]

On Sunday 14 August 2005 09:42 pm, Brent Wood wrote:
[snip]
> (Even though lakes & rivers for breaklines do not really happen on the
> seabed where I do most of my modelling :-)
>
> I'd like to make more use of GRASS for this, but have found it slow &
> cumbersome to the point of being unuseable when compared with GMT for
> generating DEM's from point data (say 20 million points).

Brent how does the gridding procedure in GMT compare to v.surf.rst ? is speed 
being gained over loss in accuracy or flexibility?

> If anyone has any ideas on how to address this & tweak performance I'd be
> grateful, or if there is any specific info I can provide to help in this
> area?

there are some nice papers on tweaking the parameters for v.surf.rst and its 
kin in the recent GRASS 2002 conference proceedings [1].

> A sort of "howto create a Spearfish-like DEM from raw point data" ??

Again, one of Helena's papers talks about how to do this, and can be found on 
her website [2] (i have the relevant PDF if you would like it, but i 
originally found it here).

1. http://www.ing.unitn.it/~grass/conferences/GRASS2002/proceedings/home.html
2. http://skagit.meas.ncsu.edu/~helena/gmslab/index.html

-- 
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341