Wednesday, June 21, 2000

Hydrogeologic : Extract data from seismic files for use in surfer

I recently found a backup storage hard disk. This hard disk holds scripts and programs going back to 1998.

This specific perl script I am posting here is/was used to extract water depth data from p190 seismic files and convert it into a format Surfer could read and in turn generate images as the one below (image source: Schlumberger Water Services)





If I were to write this today I would probably write it rather differently, but alas it worked.

Pure nostalgia.

#!/opt/perl5/bin/perl

# SUB ROUTINE DECLARATION     
sub GetFileBaseName;
sub Grab_XYZ;
sub Presentation1;
sub Presentation2;
sub Presentation3;


# VARABLE DECLARATION  
@file_list = `ls -1 *.{p190,WGS84,tc,AGD84,AGD66,WGS-84,AGD-84,AGD-66,Kertau}`;
chop @file_list;
open (OUTFILE, ">surfer_file") or die ("Could not open surfer_file.\n");


# MAIN SCRIPT FLOW
Presentation1;
foreach $file (@file_list){
  open (P190FILE, "$file") or die ("Could not open $file.\n");
  $filebasename = GetFileBaseName($file);
  $shot_record = "S" . $filebasename;
  $counter = 0;
  print ("Filebasename: $filebasename\n");  
  $line = <P190FILE>;
  while ($line ne ""){
    Grab_XYZ;
  }
  close (P190FILE);
   
  if ($counter == 0){
    $status = "FAILED";
  }
  else{
    $status = "OK";
  }
  Presentation2;
}
close (OUTFILE);
Presentation3;



# SUB ROUTINE IMPLEMENTATIONS

sub Grab_XYZ{
 if ($line =~ /$shot_record/){
   $x = substr($line,46,9);
   $y = substr($line,55,9);
   $z = -substr($line,64,6);
   print OUTFILE ("$x $y $z\n");
   $line = <P190FILE>;
   $counter++;
   #print ("$counter\n");
 }
 else{
   $line = <P190FILE>;
 }
}



sub GetFileBaseName
{
  my ($input_str) = @_;
  my ($end_pos, $temp);
  
  if ($input_str =~/_/g){
    $start_pos = pos ($input_str);
  }    
  if ($input_str =~ /\./g){
    $end_pos = pos ($input_str) - $start_pos ;
  }
  
  $temp = substr ($input_str, $start_pos, $end_pos-1);
  return ($temp);
}






sub Presentation1{
$~ = "MYFORMAT1";
write;
}

sub Presentation2{
$~ = "MYFORMAT2";
write;
}

sub Presentation3{
$~ = "MYFORMAT3";
write;
}

format MYFORMAT1 =




********************************************************************************
*           |     NUMBER OF VALUES GRABBED      |          *
*              FILE     |-----------------------------------|  STATUS  *
*    |     X     |     Y     |     Z     |          *
********************************************************************************
.


format MYFORMAT2 =
* @<<<<<<<<<<<<<<<<<<<<<<<<<<   |  @||||||  |  @||||||  |  @||||||  | @||||||| *
  $file        $counter    $counter    $counter   $status
.

format MYFORMAT3 =
********************************************************************************
* STATUS: FINISHED PROCESSING             *
* OUTPUT FILE: surfer_file                  *
********************************************************************************

Author  : Kenneth Thorman        
Script  : make_surfer_file      
Date    : 26/4 - 1999        
.


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