SeismicUnix version 4.0 was run on a Linux system to extract the navigation from the header of the seismic SEG-Y files and create SU formatted seismic files. The navigation goes into an ASCII file with the extension txt and the seismic data in the SeismicUnix format goes into a file with the extension su. The script used to accomplish this was read_ir:
# 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 or DEC or endian=1 for Sun, SGI, MAC...
segyread tape=$1.sgy verbose=1 vblock=1000 conv=1 endian=0 | \
segyclean > $1.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 " "
echo " "
echo "Writing shot navigation files to nav directory..."
echo " "
sugethw key=tracl,sx,sy,year,day,hour,minute,sec output=ascii < $1.su | \
grep tracl | 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:%02d:%02d:%02d\n", \
$4,$6,line,$2,$4/360000,$6/360000,$8,$10,$12,$14,$16} ' line=$1 - > ../nav/$1.temp.txt
sort -b -g -um -k 1,2 ../nav/$1.temp.txt | cut -f2-7 > ../nav/$1.txt rm ../nav/$1.temp.txt
This process step and all subsequent process steps were performed by the same person: VeeAnn A. Cross.