Make a plain PPM image from 3 wireline logs in a LAS file

las2ppm.awk

#!/usr/bin/gawk -f
#
# This file makes 8-bit RGB images from 3 logs
# The output is PLAIN (not RAW) PPM
# You need an LAS file containing only these logs
# Then run this script on that LAS file
# The Height should be set to the number of samples in the logs
#
# Set up the PGM Plain File format header
BEGIN {
    skipping = 1
    maxK = maxT = maxU = 1
    printf "P3\n# from las2ppm\n100 4040\n20000\n"
}
#
# Rows of pixels have the form
# r g b   r g b   r g b   r g b   r g b 
# Parse the las file and adjust the range
$1 != "~A" && skipping == 1 {next}
$1 == "~A" {skipping = 0; next}
{
if ($2 = -999.2500)
   K = 0
 else
   K = $2*1000
   
if ($3 = -999.2500)
   T = 0
 else
   T = $3*1000
   
if ($4 = -999.2500)
   U = 0
 else
   U = $4*1000
   
for (column=1; column <= 100; column++)
   {
   printf "%-10d %10d %10d\n",K, T, U
   if (maxK > K) maxK = K 
   if (maxT > T) maxT = T 
   if (maxU > T) maxU = U 
   }
}
#END {print maxK, maxT, maxU}