#!/usr/bin/perl

open (IN,"usgsdem.tab");

$maxnx = $maxny = $maxnz = 0.0;
$minnx = $minny = $minnz = 0.0;

while ($line=<IN>)
  { $line =~ s/^\s+//;
    $line =~ s/\s+$//;

    ($x,$y,$z,$nx,$ny,$nz) = split(/\s+/,$line);

    $maxnx = ($nx > $maxnx)? $nx : $maxnx;
    $minnx = ($nx < $minnx)? $nx : $minnx;
    $maxny = ($ny > $maxny)? $ny : $maxny;
    $minny = ($ny < $minny)? $ny : $minny;
    $maxnz = ($nz > $maxnz)? $nz : $maxnz;
    $minnz = ($nz < $minnz)? $nz : $minnz;
  }

printf STDOUT "Nx: %9.6f to %9.6f\n", $minnx, $maxnx;
printf STDOUT "Ny: %9.6f to %9.6f\n", $minny, $maxny;
printf STDOUT "Nz: %9.6f to %9.6f\n", $minnz, $maxnz;

close(IN);