[GRASSLIST:7901] Re: Hutchinson's Adaptive Alogrithm for sound DEMs?

Māris Nartišs maris.nartiss at gmail.com
Mon Aug 15 06:23:30 EDT 2005


when I was working on my master thesis, I was also using v.surf.rst
and was satisfied with its speed. On 5100 Bobomips machine I got about
130 points/sec. I played a lot with segmax and other parameters until
I was satisfied with results and speed.

Only easy way to speed it up would be using parallel processing. If
task could be split into multiple processes, then for large data sets
some OpenMOSIX type clusters could be used. That's would be more
important than minimal speedup for single-processor PCs.

just my 2c.


2005/8/15, Brent Wood <b.wood at niwa.co.nz>:
> On Sun, 14 Aug 2005, Dylan Beaudette wrote:
> > Maciek and other GRASS users,
> >
> > These are great points to consider. My work leads me into the realm of
> > terrain analysis, so this topic is near and dear to me. I think that it
> > would be great if the pooled efforts of the GRASS community could be
> > used to make GRASS the premier DEM creation / modification environment.
> > Since the quality of a DEM is of the utmost importance when calculating
> > primary and secondary terrain parameters, documentation of and
> > confidence in the algorithms used for DEM creation should be a
> > priority.
> >From my self-centered user perspective this is all a great idea :-)
> (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).
> 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?
> A sort of "howto create a Spearfish-like DEM from raw point data" ??
> Thanks
>   Brent

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