[GRASS5] sites (not) in 5.1
blazek at itc.it
Tue Jun 10 12:07:51 EDT 2003
On Saturday 07 June 2003 00:05, Markus Neteler wrote:
> > > The idea is to not delay 5.2 too much as vector is already there.
> > But sites isn't. That's the major off-putting factor for me; I use sites
> > all the time especially as the ASCII format is so totally simple and
> > transparent and easy to deal with. Also there is substantial sites
> > functionality that isn't present in 5.1 or else requires re-learning how
> > to do things. I'm not sure though; is there s.sample, s.surf.idw,
> > s.voronoi, things like that in the 5.1 vector functionality? Maybe there
> > is.
No. s.delaunay, s.probplt, s.sample, s.sv, s.voronoi, s.hull, s.medp, qcount,
s.surf.idw, s.territory, s.univar, s.normal, s.perturb, s.random , s.vol.rst,
s.windavg and maybe more do not have vector equivalent. There is nowbody, who
could update these modules.
> Say, it is there partially now. The idea is to use vector nodes instead of
> sites in an own format. This reduces the maintenaance efforts to two
> formats instead of three. The sites format of 5.0 is limited:
> - no NULL support
NULL is supported by DBMI in theory, but it is missing in drivers and modules.
> - troubles with strings
> - slow
Or fast. I don't think that vectors are faster. To insert more lines into postgress
(insert not copy) is so slow that it is not very usable.
> - huge files
Coordinates are almost of the same size and if you take topology + spatial index,
vector files are much bigger.
> > But it will be a big wrench to have to stop using the sites format. I'm
> > not sure of the main reasons for leaving it out (that was before I used
> > GRASS and one reason why I wanted to look at the old developers mailing
> > list). At the time the decision was made, was it presumed that there
> > would be enough programmer labour available to re-implement all the sites
> > functionality of 5.0 in the 5.1 vector functions and modules? I can't see
> > this happening although I'm not saying I wouldn't help if I thought it
> > was a worthwhile effort.
I am not sure it is worthwhile. I worry, that it is impossible to get
such performance with vector+dbmi(+driver+database) as with plaint text files.
It would be good to compare speed of v.surf.rst and s.surf.rst. But compare
and try to tune a bit rst library first.
Yes, 5.1 vector format is bad, maybe it's time to stop 5.1 development,
skip 5.2 and start 5.3.
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