[GRASS5] Re: [GRASSLIST:820] Re: Planning swath bathymetry surveys

[Hamish]

> I tried to put together a little script to test out some ideas. Things
> worked OK to a point. I ran into limits on the number of segments I
> could add to a line with v.split which limits the resolution of the
> resulting swath map. I also ran into problems with v.buffer which did
> not buffer the lines in the way I would expect. I put together a web
> page with a visual of what I mean (use the script copied below):
> 
> http://david.p.finlayson.googlepages.com/swathwidth
...
> 2) v.split out-of-memory errors?
>
> I found that v.split can not segment an input line into an arbitrary
> number of segments. The upper bound seems to be <1000 segments per
> line before getting an out of memory error.


Ok, I see a memory expansion happen, but I got ~135,000 segments for
60mb RAM. (using length=0.01 on a 1.35km line)  Happens during
"Registering lines" phase, it looks like our old friend from 
v.in.ascii points=`3 million` ?

You should be able to register a couple million line segments before you
run out of memory (c.2250 lines/megabyte) ...?


valgrind memory analysis:
 http://bambi.otago.ac.nz/hamish/grass/memleak/v.split/



Hamish