All, To print the line from an ASCII file with the maximum z-value, you could do
sort -n -k3 input_file.txt | tail -1 Bruce On Jan 6, 2008 7:56 AM, G. Allegri <[EMAIL PROTECTED]> wrote: > 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 <[EMAIL PROTECTED]>: > > > On Jan 6, 2008 12:12 AM, David Finlayson <[EMAIL PROTECTED]> 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 > > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > -- Bruce Raup http://cires.colorado.edu/~braup/ _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
