# This script converts all SEG-Y files (.sgy) in the directory it is run from to Seismic Unix (.su) format. Two navigation text files are produced from each SEG-Y file: one containing navigation and time information
# stripped from the SEG-Y header (for all traces) and one that contains the same information, but for only every 100 traces.

#! /bin/csh
foreach file (*.sgy)
# read SEG-Y standard file and convert to SU native format
  echo " "
  echo "Read SEG-Y file and output SU native format..."
  echo " "

# set endian=0 for Intel and DEC, set endian=1 for Sun, SGI...
 segyread tape=$file:r:t.sgy verbose=1 vblock=1000 conv=1 endian=0 | \
 segyclean  > $file:r:t.su

# extract SEG-Y trace header values (ffid, source x, source y, year, 
# julian day, hour, minute, second, source depth, source elevation)

#  echo " "
#  echo "Extracting SEG-Y trace header words... (ffid, source X, source Y, year, julian day, hour, minute, seconds)"
#  echo " "

 sugethw key=fldr,sx,sy,year,day,hour,minute,sec output=ascii < $file:r:t.su | \
 grep fldr | sed 's/=/	/g' | sed 's/ //g' | \
 awk '{FS="	"} {OFS="	"} {printf "%6s%7s\t%5s\t%6s\t%9.6f\t%9.6f\t%4s\t%3s:%2s:%2s:%2s\n", \
 $4,$6,line,$2,$4/360000,$6/360000,$8,$10,$12,$14,$16} ' line=$file:r:t - > ../nav/$file:r:t.temp.txt

 sort -b -g -um -k 1,2 ../nav/$file:r:t.temp.txt | cut -f2-7 > ../nav/$file:r:t.nav
 rm ../nav/$file:r:t.temp.txt


 sugethw key=fldr,sx,sy,year,day,hour,minute,sec output=ascii < $file:r:t.su | \
 grep fldr | sed 's/=/	/g' | sed 's/ //g' | \
 awk '{FS="	"} {OFS="	"} {printf "%5s	%6s	%9.6f	%9.6f	%4s	%3s:%2s:%2s:%2s\n", \
 line,$2,$4/360000,$6/360000,$8,$10,$12,$14,$16} ' line=$file:r:t - > ../nav/$file:r:t.temp.txt

awk '{if(!($2 % 100)) print;}' ../nav/$file:r:t.temp.txt > ../nav/S$file:r:t_100.nav
rm ../nav/$file:r:t.temp.txt 

  echo " "
  echo "Writing shot navigation files to nav directory..."
  echo " "
end