[GRASS-user] How to grep basic statistics from a vector ascii (x, y, z) file and export in a new ascii?

[G. Allegri]

That works for an ASCII file, but I was thinking to generalize the use
cases. Ok, passing through R would require to much RAM, but anyway I
need to use a driver to handle the binary rasters (I'm saying this
because I have a similar task but with ArcINFO GRID files).
What would you do?


2008/1/6, Markus Neteler <neteler at osgeo.org>:
> On Jan 6, 2008 12:12 AM, David Finlayson <dfinlayson at usgs.gov> wrote:
> > Your task sounds like it would be best done by a small script or C
> > program. Just read the data in a line-at-a-time and check if the
> > current line is larger than the previously stored line. At the end of
> > the file, print out the largest line (to a file if you have multiple
> > results to store). Probably 5 or 6 lines of Perl/Python at most and
> > you would be able to read arbitrarily huge files (millions of rows).
> > Most other solutions would introduce complexity or unnecessary
> > overhead. For lidar data, you may not have enough RAM to hold the
> > whole file in memory and the last thing you want to do is attach
> > topology to each point before you manipulate it.
>
> Possibly code from r.in.xyz could be recycled for v.univar to operate
> on the geometry. I also don't think that you could handle this in R, so
> a C implementation is needed.
>
> Markus
>